I get this error when trying to email out a family message to about 15 people.

"The server response was: 5.1.2 unknown host or domain: yada-yada@yahoo.com?

Use the pop-up menu below to try a different outgoing mail server. All messages will use this server until you quit Mail or change your network settings."

Says my outgoing.verizon.net can not send, but if I send 1 email at a time it works just fine.

Verizon is my primary email server/host.

Is Verizon blocking my group emails?