Currently I'm using Amazon SES, but I can not configure xenforo . I have to follow the instructions here "Amazon SES with Postfix" to use SMTP relay, but I always get an error when sending email through xenforo Check maillog Code: relay=email-smtp.us-east-1.amazonaws.com[188.8.131.52]:25, delay=2.1, delays=0/0/1.8/0.23, dsn=5.0.0, status=bounced (host email-smtp.us-east-1.amazonaws.com[184.108.40.206] said: 501 Invalid MAIL FROM address provided (in reply to MAIL FROM command)) Although I check email on the command line, there was no error occurred Code: sendmail -f email@example.com firstname.lastname@example.org From: email@example.com Subject: Test This email was sent through Amazon SES! . @eva2000 I noticed eva2000 also use SES With forums, you can guide how to configure for xenforo ? Thank !