> > Are you sending mail via SMTP directly, using 2.3.7, at a guess? > > nop. IMP 2.2.4. Dos IMP 2.2.3 support "mail via SMTP directly"? No, it doesn't. I'm afraid you'll have to do a bit more debugging to try and find the problem here - try and reproduce it in a small PHP script if you can. Anil