Hi, by hardcoding my GMX mail address in alpine-2.20/imap/src/c-client/smtp.c, i was able to prove that my workstation hostname in the "MAIL FROM:" argument is indeed the stumblestone which prevented SMTP success with gmx.net. Whew. Now i need to find out how to regularly configure the components of env->return_path to the values which yield success. Have a nice day :) Thomas