OK, There is absolutely almost no answer on the web for the MSExchangeOMA 1801 error. That’s because stock users of Exchange and IIS won’t have the issue that I had.
The very short answer: WebDav defaults to checking for stuff via IIS http on port 80.
If your IIS has another HTTP (not SSL/HTTPS) port as all it’s listening on, OMA/Outlook Mobile Access will not work. Make sure port 80 is listened to by IIS.
Why I had Internet Information Server on another port:
It was a legacy issue. I had OWA/Outlook Web Access through a firewall on a non-standard port. OWA does NOT like firewall port not matching IIS port. So HTTP port on IIS was chosen to match the firewall port for IIS for NON-SSL traffic. Later, I didn’t need non-SSL traffic for OWA and didn’t bother to change the IIS port. When OMA came up with
Unable to connect to your mailbox on server Servername. Please try again later. If the problem persists contact your administrator.
It was because it was attempting to contact internally via WebDAV on WebDAV’s default connection: http://Servername:80/Exchange/mailbox
the :80 (hidden, but the default port for web) was not accessible because my default http port on IIS wasn’t listening on port 80. This caused the same error from outside my firewall all the way to trying the OMA connection at localhost on my exchange server.
Thanks to
http://www.petri.co.il/configure_oma.htm
http://www.petri.co.il/configure_ssl_on_oma.htm
http://www.petri.co.il/test_oma_in_exchange_2003.htm
for knocking me in the head about things I didn’t realize I hadn’t done.
