If I compose and send a message with webmail the following error appears:
There was an error sending your message: unable to add recipient
[name@domain.com]: Invalid response code received from server.
Please add the following record to Server > Mail > White list in Plesk CP:
127.0.0.1 /8
If you are not able to add that record, you can also try 127.0.0.1/255.255.0.0 or 127.0.0.1/255.0.0.0
If the record is already there, you may want to remove it and then add it again. This normall is the case if you have reinstalled any of the courier/imap components on the server (This would affect the whitelist). Ultimately, if you nothing else works, you can also add the actual ip/ip’s of the server as well.
