On Sat, 18 Apr 2020 17:56:30 -0000, Bijan Tabatabai said:
> Is the problem due to the mail server banning yahoo email addresses in general?

Quite possibly.  There's reason to believe there are zero Yahoo mail accounts over
a few years old that aren't compromised, because Yahoo has gotten pwned more times
and harder than pretty much everything.

> If so, would switching to gmail or my university email solve the problem?

Likely so.

> As an additional etiquette question:
> I also CC'd the maintainer in the patch, and I believe the email got through 
> to him. When I get this problem resolved, should I CC him again when I resend
> the patch, or just send the patch to the mailing list?

Resend it to all the same recipients, but change the Subject: line from
[PATCH] to [PATCH RESEND].   If you're using a different From: address,
make a note of that in the mail.