If you are experiencing any -11 issues (when using WebMail), or if you see a blank page when setting up OAuth2 for IMAP, please see this post for full details:
https://www.esumsoft.com/blog/yahoo-mai ... nd-oauth2/
Yahoo -11 and OAuth2
Re: Yahoo -11 and OAuth2
Yahoo has not fixed the issue so v4.5.1 will be released soon. If you would like to test this, please see the following page:
https://www.esumsoft.com/pop-peeper-beta/
Please report any issues you have immediately.
https://www.esumsoft.com/pop-peeper-beta/
Please report any issues you have immediately.