Sometimes spamass-milter goes into a state sending tempfail to everything, yet nothing is logged. I have patched throw_error thus to start debugging the problem. When I gather more info I'll post it here. void throw_error(const string& errmsg) { // njh@bandsman.co.uk: if there's no current error still flag something if(errmsg.c_str()) syslog(LOG_ERR, errmsg.c_str()); else syslog(LOG_ERR, "Unknown error"); };