The User Name should be the full email address, and the authentication OAuth2. Yahoo has the same settings, except the servers are imap.mail.yahoo.com and smtp.mail.yahoo.com.

Thanks for the speedy reply.

Here are my yahoo settings (same as gmail with appropriate server names). I'm not a casual user of TB or network settings. I don't think this is a TB error. I thought it might be connected to windows updates and was hoping other TB users here had the same problem after recent updates. I didn't find any searching the community questions so I posted.

Is this a regular gmail account or a g-suite account with a custom domain? A gmail account with the correct settings should connect and display the OAuth browser window, unless you haven't enabled cookies in TB Options/Privacy.

regular gmail account (in use 10 years) and regular yahoo accounts (in use 20 years). Been using TB 15 years on every computer i've owned on every Windows OS since XP. Again, I don't think this is a TB issue, but rather a windows problem. I've done a couple updates and removal of updates in last week, so probably screwed some DLL. Was hoping is was a common problem from latest windows update, but there doesn't appear to be anyone else reporting the same problem. thanks for the help.

a couple other programs were having problems, caused by fwbase.dll and fwpuclnt.dll. I replaced these and fixed the other programs but it didn't help TB. If this gives you a clue please share.

thanks again