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[220.127.116.11]: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[18.104.22.168] 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 firstname.lastname@example.org email@example.com From: firstname.lastname@example.org 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 !