However, my filter settings on gmail only seem to relate to incoming mail. I suggested maybe I was on a Spam list, but he insists the problem must be in my gmail filter settings.

I contacted Shaw tech support and was told that there is no way to block a gmail account from sending messages to all Shaw recipients.

I suspect maybe my gmail has been put on some sort of Spam list? Even my messages to my sister's shaw account are no longer going thru with that gmail, but works fine if I send through a different gmail. When I contacted the person who supposedly blocked me via another gmail account, she said she had definitely not blocked my gmail. Today the reason said ' 554 cmsmtp Connection refused - 209.85.208.42' Last week, it said the recipient's account was over limit, but in a different message to someone else the failure message said I was blocked from sending to that account. In the past week or two, I've had 5 or 6 messages to Shaw recipients bounce back. I have a Shaw account, but the email I use is gmail.

Server email bounce back message gmail