So I am getting this message out of the blue, and I have no idea why. I don't send out that many emails, and I haven't heard from anyone they they are getting spam messages from me. What gives and what can I do?
Message could not be sent to the following recipients: [email@example.com] (554 - 554 5.2.0 http://customer.comcast.com/help-and-support/internet/limitations-on-sending-email/
If an employee doesn't reply to your message here, Comcast Security Assurance should be able to help. You can reach them at 1-888-565-4329 (from https://internetsecurity.xfinity.com/help/report-abuse/). Note that this is NOT one of the general customer service numbers.
The first-line reps there are sometimes not very helpful, so you may need to be persistent and keep at them until you get a satisfactory answer.