I am using Thunderbird. A few times recently I received spam apparently addressed to may CompuServe account. I tried to forward it to
spam@compuserve.com and it failed. I forget what the message was, but something about the server having rejected it. Within T-bird, I was forwarding from my CompuServe account, not my tapcis.com account.
The first time this happened, I thought that the outgoing server was down because other messages didn't work either. But other times that was not the case, yet the forwarded message failed.
Another question I have about this is whether, when I say "forward" in T-bird, all of the mail headers from the original message will be passed along. I have the feeling they won't, and I would have to view them first, the paste into an outgoing message.