I noticed and reported similarly to Mark, at the time when there seemed to be the general message posting problem. After it was, to some extent, cleared up, I have noticed the same SMTP error messages sometimes appearing, for just a few seconds, to be followed by an apparent confirmation that the "report this message" had actually been submitted. I tried a test PM to myself immediately after one of these. That got through ok, so I've assumed that the "report this message" ones got through too, and that the error messages were themselves false and a manifestation of the ongoing intermittent fault. But it would be useful to know if siousxiesue's one did get through or not.