CRM 4.0 Email Router POP3 Configuration
The CRM 4.0 Email Router does not allow you to specify the username when you are configuring an incoming pop connection. Then you might run into problems if the username doesn’t match the email address. It apparently uses the email address as the username (which is not always plausible or valid). I just came to this realization when I had to trace my crm router mailbox because it could not test correctly on incoming messages. I renamed my account and now it works.