možná pomůže toto k identifikaci problému:
2009/06/24 21:50:26 SMTP: AUTH LOGIN
2009/06/24 21:50:41 SMTP: 334 VXNlcm5hbWU6
2009/06/24 21:50:41 SMTP: 334 UGFzc3dvcmQ6
2009/06/24 21:50:41 SMTP: 235 #2.0.0 OK Authenticated
2009/06/24 21:50:41 SMTP: 501 #5.1.3 Partial domain not allowed: ''
2009/06/24 21:50:41 smtp error (MAIL FROM): 501 #5.1.3 Partial domain not allowed: ''
2009/06/24 21:50:41 sending E-mail to failed
2009/06/24 21:50:42 SMTP: 220 port1.iol.cz ESMTP
2009/06/24 21:50:42 SMTP: 250-port1.iol.cz