Hi, are you getting a full-page error, or do you mean that on the login form, Firefox drops down a little insecure connection warning when you click in the user name or password box?

Often the full page error will have a code similar to SEC_ERROR_SOMETHING which provides more specific information about the problem. Could you look for that and copy/paste it into a reply to this thread (https://support.mozilla.org/questions/1391037). Sometimes you need to click an Advanced button to access the code.

And as a sneak preview, this article has information about many of the codes: How to troubleshoot security error codes on secure websites.

Can you attach a screenshot?

• https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem
• use a compressed image type like PNG or JPG to save the screenshot

Are you using a proxy or VPN?

You can check the connection settings.

• Settings -> General -> Network: Connection -> Settings

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

See "Firefox connection settings":

• https://support.mozilla.org/en-US/kb/websites-dont-load-troubleshoot-and-fix-errors
• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can
• https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites