Diagnostic Code: Smtp;554 Sorry, Message Looks Like Spam To Me Changed From Yahoo To Comcast. Friends Gettin "unable To Deliver" From Yahoo Whenver They Send Mail

Changed from Yahoo to Comcast. Friends gettin "unable to deliver" from Yahoo whenver they send mail - diagnostic code: smtp;554 sorry, message looks like spam to me

Uninstalled all Yahoo, esp. Because of problems with e-mail.
Let's go to Comcast.net, my server for your mail program. Become friends "advice" undeliverable Yahoo every time I e-mail, even if the mail gets through.
Yahoo Mail: Status: 5.1.0. Rossglen@comcast.net Mail> 554 Response: 554_delivery_error_dd_Sorry_your_message ...
@ Yahoo.com_cannot_be_delivered_Thisacc ... has been disabled or discontinued_ [# 102 ]._-_ mta553.mail.mud.y ... Diagnostic-Code: SMTP permanent error: The level of a different direction.