Authentication Failing with known Good Creds

[Gary]

For the Yahoo issue, see if this is any help:

FIXED! Yahoo Accounts and eM Client

UPDATE 11/24/2020 Three weeks ago (11/08/2020) our oAuth registration at the Yahoo Developer Portal became misconfigured - so a Yahoo! account could not be set up via the Automatic setup. We have contacted Yahoo Developer support to resolve the issue and they finally fixed the registration for eM Client. Because some permissions were renamed by Yahoo! a new version of eM Client is required. Please download the fixed version here: eM Client 7 for Windows: https://www.emclient.com/dist/v7.2.50…