Is the authentication method OAuth2, for Yahoo and gmail, for the incoming and outgoing servers?

Yes it is

Don't know if this will make a difference but fyi I just set up em client and it all works perfect there

I would still prefer thunderbird though if anyone can help me figure out this issue

Em client has some settings thunderbird does not seem to have

Like for imap security policy is use SSL/TLS on special port (legacy)

And smtp has security saying force usage os SSL/TLS

Try removing the entries for the accounts, imap://, smtp:// and oauth://, from Saved Passwords in TB, check that cookies are accepted in TB Settings/Privacy & Security, disable a VPN if one is used, restart TB, enter the account password in the OAuth window to allow access.

The EmClient settings are not more helpful than the ones provided by TB.

When I click on saved passwords, there is nothing there.

Cookies are allowed always

No VPN is involved

Don't know where the OAuth window is

When i restart it goes back to the beginning of setting up an account so it is not retaining any of the previous info entered

The only OA UT H locations I can find are dropdown boxes that will not allow me to type in a password. There must be something that I'm missing or not understanding from what you're telling me.

The Oauth browser-like window appears on first connection and is where you enter the account password. When the authentication completes, an oauth:// entry is added to Saved Passwords.

There are millions of gmail accounts working in TB, so there must be some external app that's interfering. Some antivirus apps like Norton have password managers.