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How to Fix Your Connection is Not Secure in Firefox

Authored by:
Support.com Tech Pro Team
This Guided Path® was written and reviewed by Support.com’s Tech Pro team. With decades of experience, our Tech Pros are passionate about making technology work for you. We love feedback! Let us know what you think about this Guided Path® by rating it at the end.

Introduction

Mozilla likes secure websites. Websites that start with https:// have purchased a certificate and are specially encrypted to protect you. Websites that do not have that encryption are seen as unsafe by Firefox and you'll receive this warning.

Not being able to access your regular sites while browsing can be frustrating. In many cases, they are caused by a website that's not configured properly, but you can double check your date and time and clear your Firefox history to make sure it isn't on your end.

This guide will take you through the basic settings to ensure your computer and Firefox aren't the cause of these security errors. We will check:

  • Computer date and time
  • Firefox cache and cookies
Firefox security warning.

1 Make Sure Date and Time are Correct

Security certificates are used by our web browsers and computers to make sure a particular site is safe. If the date and time are wrong, certain web pages may give security warnings and secure programs such as work VPNs, banking apps, and most social network apps will not function. Since iOS devices (iPhones and iPads) and Android set their time automatically, you don't usually need to check those.

If you notice that your Date and Time keeps becoming unsynced, you should speak to the manufacturer about replacing your CMOS battery.

How to Verify the Date and Time on a Mac

  1. Select the time display in the top-right corner of your screen.
  2. Make sure both the date and time are correct.
    Mac Menu Bar with time menu and date highlighted.
  3. If the time is incorrect, select the time display in the top-right corner of your screen, then select Open Date & Time Preferences.
    Time display with Open Date and Time Preferences highlighted.
  4. Select the lock in the bottom-left corner to make changes.
    Date and Time preferences with lock highlighted.
  5. Enter your username and password, then select Unlock.
    Unlock prompt with user name, password, and unlock button highlighted.
  6. In most cases, letting your Mac take care of setting the time is the best choice. Make sure there is a check for Set date and time automatically, and make sure a time server close to you is chosen.
    Date and Time preferences with Set date and time automatically highlighted.
  7. If you want, you can set the time manually. Remove the check for Set date and time automatically, then enter the correct date and time. Press Save when done.
    Date and Time Preferences with Set date and time automatically unchecked, with calendar, clock, and save button highlighted.
  8. Select Time Zone, then select your closest region on the map, and refine it by choosing the city you are in, or the city closest to you, from the list below.
    Date and Time Preferences with Time Zone, Map, and Closest City highlighted.

How to Verify the Date and Time in Windows

  1. Look at the date and time shown in the system tray. This is usually in the bottom right corner of the screen.
    Windows 10 Taskbar with Date and Time highlighted.
  2. If the date or time are wrong, it can cause issues. To fix:

    Windows 10

    1. Right-click on the date and time.
      Windows 10 Taskbar with Date and Time highlighted.
    2. Select Adjust date/time.
      Context menu for clock with Adjust date time highlighted.
    3. For most, letting Windows manage the date and time, as well as automatically setting it is the best choice.
      1. Make sure Set time automatically and Adjust for daylight saving time automatically are both turned On.
        Date and time settings with Set time automatically and Adjust for daylight saving time automatically highlighted.
      2. Make sure your time zone is selected for Time zone.
        Date and time settings with Time zone highlighted.
    4. If you want, you can manually set the Date and time.
      1. Make sure Set time automatically is set to Off, then select Change for Change date and time.
        Date and time settings with set time automatically off, and change date and time highlighted.
      2. Set the Date and Time correctly, then select Change.
        Date and time dialog with date, time, and change button highlighted.

    Other Windows Versions

    1. Right-click on the date and time.
      Windows 7 task bar with date and time highlighted.
    2. Select Adjust date/time.
      Date and time context menu with Adjust date time highlighted.
    3. Make sure the proper Time zone is selected.
      Date and time settings with Time zone highlighted.
    4. Select Change date and time.
      Date and time options with Change date and time highlighted.
    5. Correct the Date and Time, then select OK.
      Date and time settings with calendar, time, and OK button highlighted.
    6. You may wish to have Windows set the date and time for you in the future.
      1. Select the Internet Time tab at the top, then select Change settings.
        Date and time with Internet Time tab and Change settings highlighted.
      2. Make sure Synchronize with an Internet time server is checked, then select OK.
        Internet time settings with Synchronize and OK button highlighted.

2 Clearing the Browser History and Cache

If you're still having issues with the website, you may have a corrupt cookie or your browser history could be saving the wrong version of the site. Clearing the browsing data will fix this.

Clear the Browser Data on a Mac

  1. Open Mozilla Firefox.
    Mozilla Firefox.
  2. Select the Menu button located in the top right corner of the window.
    Firefox menu
  3. Select Library.
    Firefox Menu with Library highlighted.
  4. Select History.
    Library with History highlighted.
  5. Select Clear Recent History.
    History with Clear Recent History highlighted.
  6. For Time range to clear, select Everything. Then select Clear Now.
    Clear history with Time range and Clear Now button highlighted.

Clear the Browser Data in Windows

  1. Open Mozilla Firefox.
    Mozilla Firefox Icon
  2. Click the Menu button in the top right of the screen.
    Firefox menu
  3. Click on Options.
    Options highlighted
  4. Click on Privacy & Security.
    Privacy & Security highlighted
  5. Click the Clear History button located under the History category.
    Clear History button highlighted
  6. Select the Everything to clear all your Firefox browser history.
    Clearing all history by selecting everything.
  7. Click the Details button to expand them.
    Details expand button highlighted
  8. Choose the item categories you wish to clear. We recommend selecting everything to make sure the issue is fixed. Keep in mind you will have to re-login into websites if you do this.
    Item categories highlighted 
  9. Click the Clear Now button.
    Clear Now button highlighted

3 Try the Webpage Again

Once cleaned up, try the website again. If you're still having issues it is most likely caused by the site itself. To resolve this, you'll need to get in contact with the webmaster and let them know. If that's not possible you'll just have to wait.

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Mozilla likes secure websites. Websites that start with https:// have purchased a certificate and are specially encrypted to protect you. Websites that do not have that encryption are seen as unsafe by Firefox and you'll receive this warning.

Not being able to access your regular sites while browsing can be frustrating. In many cases, they are caused by a website that's not configured properly, but you can double check your date and time and clear your Firefox history to make sure it isn't on your end.

This guide will take you through the basic settings to ensure your computer and Firefox aren't the cause of these security errors. We will check:

  • Computer date and time
  • Firefox cache and cookies
Firefox security warning.

Security certificates are used by our web browsers and computers to make sure a particular site is safe. If the date and time are wrong, certain web pages may give security warnings and secure programs such as work VPNs, banking apps, and most social network apps will not function. Since iOS devices (iPhones and iPads) and Android set their time automatically, you don't usually need to check those.

If you notice that your Date and Time keeps becoming unsynced, you should speak to the manufacturer about replacing your CMOS battery.

How to Verify the Date and Time on a Mac

  1. Select the time display in the top-right corner of your screen.
  2. Make sure both the date and time are correct.
    Mac Menu Bar with time menu and date highlighted.
  3. If the time is incorrect, select the time display in the top-right corner of your screen, then select Open Date & Time Preferences.
    Time display with Open Date and Time Preferences highlighted.
  4. Select the lock in the bottom-left corner to make changes.
    Date and Time preferences with lock highlighted.
  5. Enter your username and password, then select Unlock.
    Unlock prompt with user name, password, and unlock button highlighted.
  6. In most cases, letting your Mac take care of setting the time is the best choice. Make sure there is a check for Set date and time automatically, and make sure a time server close to you is chosen.
    Date and Time preferences with Set date and time automatically highlighted.
  7. If you want, you can set the time manually. Remove the check for Set date and time automatically, then enter the correct date and time. Press Save when done.
    Date and Time Preferences with Set date and time automatically unchecked, with calendar, clock, and save button highlighted.
  8. Select Time Zone, then select your closest region on the map, and refine it by choosing the city you are in, or the city closest to you, from the list below.
    Date and Time Preferences with Time Zone, Map, and Closest City highlighted.

How to Verify the Date and Time in Windows

  1. Look at the date and time shown in the system tray. This is usually in the bottom right corner of the screen.
    Windows 10 Taskbar with Date and Time highlighted.
  2. If the date or time are wrong, it can cause issues. To fix:

    Windows 10

    1. Right-click on the date and time.
      Windows 10 Taskbar with Date and Time highlighted.
    2. Select Adjust date/time.
      Context menu for clock with Adjust date time highlighted.
    3. For most, letting Windows manage the date and time, as well as automatically setting it is the best choice.
      1. Make sure Set time automatically and Adjust for daylight saving time automatically are both turned On.
        Date and time settings with Set time automatically and Adjust for daylight saving time automatically highlighted.
      2. Make sure your time zone is selected for Time zone.
        Date and time settings with Time zone highlighted.
    4. If you want, you can manually set the Date and time.
      1. Make sure Set time automatically is set to Off, then select Change for Change date and time.
        Date and time settings with set time automatically off, and change date and time highlighted.
      2. Set the Date and Time correctly, then select Change.
        Date and time dialog with date, time, and change button highlighted.

    Other Windows Versions

    1. Right-click on the date and time.
      Windows 7 task bar with date and time highlighted.
    2. Select Adjust date/time.
      Date and time context menu with Adjust date time highlighted.
    3. Make sure the proper Time zone is selected.
      Date and time settings with Time zone highlighted.
    4. Select Change date and time.
      Date and time options with Change date and time highlighted.
    5. Correct the Date and Time, then select OK.
      Date and time settings with calendar, time, and OK button highlighted.
    6. You may wish to have Windows set the date and time for you in the future.
      1. Select the Internet Time tab at the top, then select Change settings.
        Date and time with Internet Time tab and Change settings highlighted.
      2. Make sure Synchronize with an Internet time server is checked, then select OK.
        Internet time settings with Synchronize and OK button highlighted.
If you're still having issues with the website, you may have a corrupt cookie or your browser history could be saving the wrong version of the site. Clearing the browsing data will fix this.

Clear the Browser Data on a Mac

  1. Open Mozilla Firefox.
    Mozilla Firefox.
  2. Select the Menu button located in the top right corner of the window.
    Firefox menu
  3. Select Library.
    Firefox Menu with Library highlighted.
  4. Select History.
    Library with History highlighted.
  5. Select Clear Recent History.
    History with Clear Recent History highlighted.
  6. For Time range to clear, select Everything. Then select Clear Now.
    Clear history with Time range and Clear Now button highlighted.

Clear the Browser Data in Windows

  1. Open Mozilla Firefox.
    Mozilla Firefox Icon
  2. Click the Menu button in the top right of the screen.
    Firefox menu
  3. Click on Options.
    Options highlighted
  4. Click on Privacy & Security.
    Privacy & Security highlighted
  5. Click the Clear History button located under the History category.
    Clear History button highlighted
  6. Select the Everything to clear all your Firefox browser history.
    Clearing all history by selecting everything.
  7. Click the Details button to expand them.
    Details expand button highlighted
  8. Choose the item categories you wish to clear. We recommend selecting everything to make sure the issue is fixed. Keep in mind you will have to re-login into websites if you do this.
    Item categories highlighted 
  9. Click the Clear Now button.
    Clear Now button highlighted

Once cleaned up, try the website again. If you're still having issues it is most likely caused by the site itself. To resolve this, you'll need to get in contact with the webmaster and let them know. If that's not possible you'll just have to wait.