Ok, I see.
Please try next:
1) Switch off 'Use different credentials for SMTP' + Plain SMTP (Outgoing SMTP port is unchecked)
2) Switch off 'Use different credentials for SMTP' + SSL SMTP (Outgoing SMTP port is checked)
3) Switch on 'Use different credentials for SMTP', but leave Username & passwords empty + Plain SMTP (Outgoing SMTP port is unchecked)
4) Switch on 'Use different credentials for SMTP', but leave Username & passwords empty + SSL SMTP (Outgoing SMTP port is checked)
