Event 5740 and 5649 with POP3 authentication and Biztalk Server

During the configuration of the Biztalk 2010 POP3 connector, I had some trouble finding the correct authentication method. The following errors kept showing up in my eventlog:

Source:        BizTalk Server
Event ID:      5740
Task Category: BizTalk Server
Level:         Warning
The adapter “POP3” raised an error message. Details “The POP3 server does not support the specified authentication scheme.
Please change the scheme to the one supported by POP3 server.
URL: POP3://exchangeserver#domain\useraccount
Scheme: SPA
Error: -ERR Command is not valid in this state. “.


Source:        BizTalk Server
Event ID:      5649
Task Category: BizTalk Server
Level:         Error
The receive location “Message-POP” with URL “POP3://exchangeserver#domain\useraccount” is shutting down. Details:”The POP3 adapter is shutting down because it exceeded error threshold.
URL: POP3://exchangeserver#domain\useraccount”.

In my Exchange 2007 organization, the POP3 connector is set as follows:


Because the server side is set to “Secure Logon. A TLS connection is required for the client to authenticate to the server”, you have to set the client to SPA (Secure Password Authentication) with SSL enabled.

Therefor, I set the POP3 client in Biztalk to the following:


At the Security section, make sure you have the Authentication Scheme set to SPA, “Use SSL” to True, and User Name as domain\username.

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