Configuring Mail Adapter as sender

Hello,

I'd like to ask for some help with configuration of SAP XI mail adapter as sender. I made a communication chanel with mail adapter type and specified transport protocol POP3, URL (pop3://localhost), user, password and poll interval. The problem is that XI doesn't trigger the

process, in other words it doesn't connect to my email server to receive the mail. What could be wrong? To test the environment, I made a test case withmail adapter as a receiver - and it works ok - it sends mail via my email server - so SMTP is working fine.

Thank you,

Igor