Is it just the webmail server (public? work? homebrew?) that you have trouble with, or other HTTPS connections as well?

I can see cookies, bad connection settings and malware mentioned in other online posts as the cause:

• http://community.mozy.com/t5/Mozy-for-Windows/quot-secure-connection-failed-quot-on-Firefox-quot/td-p/82680
• http://www.sevenforums.com/browsers-mail/301466-mozilla-firefox-error-connection-reset-3.html
• https://support.mozilla.org/en-US/questions/1039425

Other than that, I can only suspect certificates, but the error is not "Your connection is not secure".

PS. Does the error persist in Private Mode? https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history#w_how-do-i-open-a-new-private-window

See:

• https://support.mozilla.org/kb/troubleshoot-SEC_ERROR_UNKNOWN_ISSUER

Phoxuponyou said

PS. Does the error persist in Private Mode?

The error does not persist in a private mode window

Phoxuponyou said

Is it just the webmail server (public? work? homebrew?) that you have trouble with, or other HTTPS connections as well? I can see cookies, bad connection settings and malware mentioned in other online posts as the cause:

I have already cleared the cache, temp internet files and cookies.

The webmail accounts are on a server on my webhost. The error only occurs on that server. Other https connections work fine

Alright, so HTTPS works in general, it's just one domain/host/site that has trouble.

T1234 said

Phoxuponyou said

PS. Does the error persist in Private Mode?

The error does not persist in a private mode window

I wanted to test Private Mode because it uses a clean cache and separate cookie jar - if Private Mode works, this suggests more cleanup is needed.

Since it's just one site, let's try the following:

1. Browse to the troubled host's URL in Firefox.
2. Once the host URL tab has loaded, open a blank tab and close all other tabs.
3. Go to the Firefox main menu by clicking the three-bar sandwich icon.
4. Select History.
5. Select Show All History.
6. Search for the troubled host URL in the Library view that has opened up (e.g. "webmail" or "webmail.mydomain.com"; the broader the search the better so you can catch all entries).
7. Right-click on one of the matched entries and select Forget About This Site from the drop-down menu. Continue until all matches are gone.
8. Restart Firefox and try the webmail host again.

This is a site-specific cleanup so you don't have to lose all your cookies over this.

You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History > Show All History" or "View > Sidebar > History").

Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks and history and cookies and passwords and cache and exceptions, so be cautious. If you have a password or other data from that domain that you do not want to lose then make sure to backup this data or make a note.

Can't recover from this 'forget' unless you have a backup of involved files.

If you revisit a 'forgotten' website then data from that website will be saved once again.

I tried the "forget this site" and it did not fix the problem

Try to rename the cert8.db file (cert8.db.old) to see if that helps in case you have stored an intermediate certificate that is causing problems.

If that has helped to solve the problem then you can remove the renamed cert8.db.old file. Otherwise you can rename/copy cert8.db.old to cert8.db to restore previously stored intermediate certificates. Firefox will automatically store intermediate certificates that servers send in the Certificate Manager for future use.

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

cor-el said

Try to rename the cert8.db file (cert8.db.old) to see if that helps in case you have stored an intermediate certificate that is causing problems. If that has helped to solve the problem then you can remove the renamed cert8.db.old file. Otherwise you can rename/copy cert8.db.old to cert8.db to restore previously stored intermediate certificates. Firefox will automatically store intermediate certificates that servers send in the Certificate Manager for future use. You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

This did not fix the problem

Create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I tried creating and using a new profile as per the instructions and it did not solve the problem