troubles with email reader

Having issues setting up the email reader in service desk. We get this error after adding a reader

Rebex.Net.ImapException: Invalid IMAP response. at ServiceDesk.ProcessEmail.HandleEmlReader.HandleIMAP(Boolean IsEmailLogging, String LogFileName) in C:\dev\serviceDesk\branches\serviceDesk-v1.4.0.0\source\ServiceDesk.ProcessEmail\HandleEmlReader.cs:line 541

Please help.