Personal Email Server

I have my own domain name, so I have my own email server. The router supplied by AT&T (Pace model 5268AC) opens SMTP Server port 25 to send emails which I assigned to my server. I have no issues receiving emails via the appropriate port. I am unable to send emails. I'm quite confident my configurations are correct, but I am attempting to rule out issues. Does AT&T allow personal home email servers to send emails? Is this something I need to request? Thank you.