I have several yahoo accounts in poppeeper and one of them started throwing an error today. I tried deleting and recreating the account several times (using oauth every time) and still got an error. I updated my poppeeper to the latest version as well as deleting and recreating the account after that even. I still get the same error:
If you were able to get the "authentication successful" message after completing the Pop Peeper OAuth2 procedure for this account then this error is presumably a Yahoo issue that will ultimately get resolved on Yahoo's end at some point.
If the error stops occurring then please let us know at that time. On the other hand, if the error persists beyond 24-48 hours then please return to this topic to let us know. (Note: I assume you are able to successfully login to this account on-line using your browser).
Good judgment comes from experience and a lot of that comes from bad judgment. - Will Rogers
and thanks for getting back to us - it was apparently a Yahoo server issue specific to this account.