wp7geek, over at myWindowsPhone, has gone into some detail about how he couldn't access SharePoint via the Office Hub, but could successfully connect in the IE mobile browser. Upon attempting to connect from the Office Hub, the following error message was displayed: 

Sharepoint doesn't support this authentication scheme. For assistance contact the person who manages this SharePoint site. You can try opening the content in your web browser instead. 

wp7geek moved onto explain the cause of this error, which is apparently due to WP7 not supporting NTLM authentication that is used to login on hosted SharePoint servers. While a workaround is possible until Office Hub is updated, it requires changes on the server side of the connection, which involves contacting your host. They would need to either:

  • Deploy a Forefront UAG server (UAG settings are built into Office hub)
  • Enable Forms Based Authentication on the SharePoint Site

Forms Based Authentication (FBA) is basically creating your own login method. To authenticate, a SQL Server, XML, Windows Live IDs, etc can be used. Existing Windows Identities must be migrated to FBA identities to avoid multiple SharePoint identities for a single person. This makes it problematic for hosting companies who may have huge internal SharePoint deployments which reply on windows authentication.

Should you not have the above authentication implemented then you should be able to access the server through Office Hub, but unfortunately if they're not present then you're stuck with IE on your phone for SharePoint. 

Have you experienced problems with this issue?

Source: myWindowsPhone