On 3 April 2014 10:35, Martin Liška wrote: > Hello, > today I sent an email that returned as undelivered. The mail contains > bzip2 attachment and is standard reply in mailing list. Could you please > help me what's wrong with that: Was it definitely rejected because of the spam threshold? (You didn't show the server response). Was it an HTML mail? (The GCC lists only accept plain text.) How big was the .bz2?