I have an Exchange 2003 org that I have added an Exchange 2010 CAS to.
I have configured an external DNS record for activesync.domain.com and port 443 is allowed through the firewall to the CAS server. I am trying to test AS connectivity via the testoutlookconnectivity.com tool.
I am getting this error:
An ActiveSync session is being attempted with the server.
Errors were encountered while testing the Exchange ActiveSync session.
Attempting to send the OPTIONS command to the server.
Testing of the OPTIONS command failed. For more information, see Additional Details.
An HTTP 401 Unauthorized response was received from the remote IIS7 server. This is usually the result of an incorrect username or password. If you are attempting to log onto an Office 365 service, ensure you are using your full User Principal Name (UPN).