The System Details shows that you have several content blocking extensions installed.

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, DuckDuckGo PE, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Try downloading another copy of Firefox, run it from the folder and see if you have the same issue.

https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

The System Details shows that you have several content blocking extensions installed. If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, DuckDuckGo PE, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Thanks for the response. In the course of chasing this issue, I have tried disabling all of the above together and in combinations. Also blocked/reinstalled Javascript. Spent hours on this over the last week+, had some additional suggestions on the Ask Woody forum, and an experienced user there revealed that he had a similar issue some time back that resolved itself after a couple of months.

Try downloading another copy of Firefox, run it from the folder and see if you have the same issue. https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

This is a good suggestion that I had not previously thought of. For the moment, as noted above, I have a workaround, but once I catch up with the rest of my life I'll try it, many thanks.

Just installed offered updates, see attached s/shot, one at a time, and tried that problem log-in after each update, same error message. Next tried creating a new account on the site using different credentials, same error message again. Out of ideas...

You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

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.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

You can create a new profile as a quick test to see if your current profile is causing the problem. See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

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.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Thank you. As a non-tech, I'm not substantially versed in troubleshooting. Will be able to pursue this suggestion this week. Also have advice from elsewhere re checking for disk errors, also on the to-do list. It does appear that whatever the problem is, it's within this machine.

Try downloading another copy of Firefox, run it from the folder and see if you have the same issue. https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

Tried this, apparently did something wrong, now seem to have two instances of FF 97.0.2 installed. Both show the same site log-in error. Currently offered update of v. 98.0. If I download and install this version rather than go with the update, could be a "fresh start." I would then need to uninstall 1 (or 2) of the old FF and hopefully save my 100+ bookmarks. As a non-tech, could use some guidance here.

You may have 2 versions of FF 97.0.2, one should be your distro and the other if from Mozilla. I would use Sync to share your data across the different version of Firefox. https://support.mozilla.org/en-US/kb/how-do-i-set-sync-my-computer

I run 5 versions of Firefox plus my distro version. I sync about 3 of the browsers so they all my data in case one goes boom. see old screenshots

Thanks both for your input on this. Any thoughts on whether the 98.0 update is a full replacement for 97.0.2? It does seem that the problem is limited to the FF instance on this machine, as our other computer, same specs, installed updates, etc. readily logs into that same site, a paid newspaper subscription.

The previous FF update from 97.0.1 to 97.0.2 had no effect on the problem, OS disk checks out 100%, no bad sectors, etc. I would use the v. 98 update if it replaces all of 97.0.2, otherwise I'd be inclined to download v.98 from Mozilla.

You can check the "Help -> More Troubleshooting Information" (about:support) page for info about the installation folder and the update channel.

• https://support.mozilla.org/en-US/kb/use-troubleshooting-information-page-fix-firefox

In F/F, I have tried disabling extensions, allowing all trackers and cookies, and reinstalling Javascript,

Not sure what you mean by reinstalling JavaScript in Fx and JavaScript is built in Fx.

If you mean the Java Plugin from Oracle well Fx has not allowed the Java Plugin to run since Fx 52.0 and JavaScript and Java are two separate things. http://kb.mozillazine.org/JavaScript_is_not_Java https://support.mozilla.org/en-US/kb/npapi-plugins

stevenartigas said

In F/F, I have tried disabling extensions, allowing all trackers and cookies, and reinstalling Javascript,

Not sure what you mean by reinstalling JavaScript in Fx and JavaScript is built in Fx.

If you mean the Java Plugin from Oracle well Fx has not allowed the Java Plugin to run since Fx 52.0 and JavaScript and Java are two separate things. http://kb.mozillazine.org/JavaScript_is_not_Java https://support.mozilla.org/en-US/kb/npapi-plugins

See attachment on first post above, a s/shot of the error message. My terminology is inaccurate, should have said re-enabling, not reinstalling.

At this point, seems the best strategy is to update to FF v. 98.0. If the error is corrected, I'm good to go. If not, at least I'm chasing it in the current FF.

All efforts to repair that site log-in issue have failed- my thanks to the responders. The offered update to v. 98.0 did not change anything. My current thought is to remove FF completely using sudo apt-get --purge remove firefox 98.0 and download a new copy of FF from Mozilla using a different browser.

About to execute the FF remove/replace operation. Bookmarks saved. But I'm getting conflicting advice on the Terminal command(s) to remove FF completely, including any config files. I'm afraid if I don't start with a completely clean slate that the error I'm chasing will persist.

This mystery is solved. The replace FF initiative is unnecessary. Turns out my prolonged recovery effort evolving from that original site log-in error was hampered by a failing mouse.

Once the mouse was replaced, the "refresh FF" option on the about:support screen did just that, and the log-in error is now cured. Postmortem is that the original error was in fact a stumble within FF, and although that site log-in did not involve any mouse action, the recovery and refresh did, and the defective mouse caused weird things to happen.

My grateful thanks to all who responded to my request for assistance.