Hi. I received the following Failure Notice.

"Sorry, we were unable to deliver your message to the following address.
xxxxxxx
Error code 475: Suspicious activity was detected on your account"

May i know what should I do? I m not doing any illegal activities, i just sending almost same contains Notice to my customers (not in bulk email but in single email).

Does it mean i can no longer send to the above address? Please help. thanks