there is also a msg on the bottom left after a failed attempt stating "Sync encountered an error while synching. Failed to connect to the server..."

Try to rename the cert8.db file in the Firefox profile folder to cert8.db.old or delete the cert8.db file to remove intermediate certificates that Firefox has stored.
If that helped to solve the problem then you can remove the renamed cert8.db.old file.
Otherwise you can rename (or copy) the cert8.db.old file to cert8.db to restore the previous intermediate certificates.
Firefox will automatically store intermediate certificates when you visit websites that send such a certificate.

If that didn't help then remove or rename secmod.db (secmod.db.old) as well.

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

• Help > Troubleshooting Information > Profile Directory: Show Folder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

I see a folder named- cert8 and it is a Data Base File but I don't see a cert8.db named folder. Should I change it to cert8.old after closing Firefox?

Windows is probably hiding the .db file extension if you do not see it and the file type is Data Base File.

Note that if you rename a file with a hidden file extension that Windows will only let you change the name part and not the file extension, so you will get cert8.old.db, but that doesn't matter in this case.

started working ystrdy right after I downloaded an update for an add-on. Don't know if that had anything to do w/ it or was just an coincidence.