A thought born out of my own misery: I only had a problem if the faulty email address belonged to the ISP I was sending from, otherwise no problem (the message may bounce, but no exception will be thrown). As an ugly first solution, I would be tempted to separate emails sent to the same ISP as my mail server, send the non-associated emails (which won't throw and exception if the addresses are incorrect), and then experiment with the associated ones (you will be told which addresses are faulty in the Exceptions: eliminate them.)

I aien't no expert, and there may well be better solutions out there. But I appreciate any help I can get when faced with an intractable problem.

John S.

Aylmer, PQ.