I don't see anything obviously wrong with your setup. What version of Camel are you using? Perhaps you could also show your whole route definition. It may help to enable the tracer to see whats going on during processing http://activemq.apache.org/camel/tracer.html
Thanks, but it appears that it was the mail server after all. If I send the mail to for instance a hotmail smtp server it suddenly works, but with our mail server it works "occasionally". Still don't get why, but I assume the problem is the mail server and not the camel component.
Hmmm... thats too bad. If it was a Camel error I could have fixed it for you Just curious, the debug logs and tracer showed nothing of interest?
No, I couldn't find anything of interest, but I haven't spent so much time on it since trying with different smtp servers showed that ours was the only one messing things up. I think the error is on the receive side, possibly some kind of spam filter that is hidden from me...
Maybe taking a look at the mail server logs would help (if you have permission to do so)?