Problems that may occur are connection problems to the outbound server and timeouts by retrieving emails via POP3 / IMAP.

A Possible cause is an activated local antivirus scanner with an email check, a central antivirus scanner or firewall in the network.

For testing purposes you could disable the antivirus scanner and check for further errors. If this does not help, please contact our support with detailed information about your account, email program and all error messages (including error codes).