Message rejected by content filter

Thats the error i get when i try and send a message from my yahoo webmail account to my mochamail account. I also cannot get emails from my friends with yahoo accounts. I have deleted every filter, contact, and everything else in my mochamail account but it still rejects yahoo. I immediately of course assume it's a mochamail issue but having set my entire mochamail settings back to as they were after the moment i signed up and it still happens, i gotta ask in case theres something i may be missing. I wouldn't even use the mocha account anymore but i have had it since i first went online in the lat 90's and have a trillion contacts with it so i'd really like to figure this out. Thanks.

HI IKJ,
I'd have a look at your
AV mail settings,
Firewall (AV/MS)
And your browser restriction settings as well.,
and are your browsers upto date

Roy

I've done all that. But note that my browser should have nothing to do with it when i use outllook 2013 from office and people with yahoo get rejected. I doubt all thier browsers are exactly the same.

Hi IKJ,
You could try un-installing/re-installing Yahoo mail.

Roy

I think i found the reason, tho i don't understand it or how to get around it...
https://help.yahoo.com/kb/SLN24016.html

Hi IKJ,
God thats totally uninformative, apart from from one word DOMAIN.
The only thing i can think you can do is move away from a domain setting to personnal.
Dont use Yahoo so i dont know if even this will work.

Roy

Yeah, and to make it more confusing i really can't be sure who;s to blame, yahoo or mochamail. The failed messages say "rejected by content filter but there are no filters active on my mochamail account, and even when i did have some they had nothing to do with yahoo.