I cannot receive Yahoo.com emails to my main TWC.com email address. I've sent test messages to both my @Twc.com addresses and one goes thru to my alternate but not to the main address I use. I initially thought the problem was with Microsoft Outlook but signing-in via browser presents the same problem. Why would they go to one but not the other?
Yahoo.com was apparently acquired by AT&T a while back. They are having ongoing problems consolidating all the various AT&T and Yahoo emal domains onto a single server farm. Unlucky me, I have email accounts with both of them and also Google. Google is the most reliable and least screwed up so far.
You probably will need to complain to both AT&T and Spectrum, who may have flagged Yahoo or AT&T as spammers because they send hundreds of messages at a time to Spectrum's email site and those of several other large email operators including Google and Microsoft.