There are three common reasons why you may be able to receive, but unable to send emails.
- Your Internet Service Provider is blocking port 25, which is the default outgoing mail port.
Solution: change the outgoing mail port to 587. If you're not sure how to do that, you can go back through the Knowledge article for your email program (they're listed under Edit Site -> Domains & EMail -> Email (on the left) and where it normally says to set the port to 25, just enter 587).
- Your Anti-Virus or Firewall software may be interfering with your connection.
Solution: temporarily disable your anti-virus or firewall software, and try sending an email again. If you are able to send the email, your anti-virus software is the culprit and you can go through your anti-virus settings to disable the feature that is causing problems. If you still have issues sending, the problem is elsewhere.
- Your Outgoing mail settings could be wrong. This normally results in an error message that refers to 'Relay Access Denied'.
Solution: Review the Knowledge Base article you used to set up your email program originally, paying special attention to the last few settings. Every email program is a little different, but most have an option similar to 'My Outgoing Mail Server requires Authentication'. That settings needs to be enabled, and it needs to be using the same email address and password that you use to receive emails (those can be set under Edit Site -> Domains & EMail -> Email)
For your reference, these are the ports that you can connect to our Outgoing Email servers (SMTP) on:
Outgoing Mail Ports:
25 (Disable SSL security)
587 (Disable SSL security)
465 (Enable SSL security)