In Nokia Belle (and Symbian Anna), when there is a policy which is not supported, Exchange server may not allow the sync based on one or more of the server settings. For example the roaming policy may be the one causing the failure, Policy SyncWhileRoaming =1 on the admin log.
However this can happen due to any unsupported policy.
You can identify the problem on the policy and if necessary, then the administrator can toggle it, or set the tick box Allow non provisionable devices on the Exchange server (Wording of this setting can vary by locale and Exchange server version.). Otherwise, the device may not sync.
To confirm this is causing the issue, you can open the admin logs and compare them to this table:
10/07/2011 17:17:32 Policy AllowTextMessaging = 110/07/2011 17:17:32 Policy SyncWhileRoaming = 010/07/2011 17:17:32 Policy AllowHtmlEmail = 110/07/2011 17:17:32 Policy RequireSignedSMIMEMessages = 010/07/2011 17:17:32 Policy RequireEncryptedSMIMEMessages = 010/07/2011 17:17:32 Policy RequireSignedSMIMEAlgorithm = 010/07/2011 17:17:32 Policy RequireEncryptionSMIMEAlgorithm = 010/07/2011 17:17:32 Policy AllowUnsignedApplications = 110/07/2011 17:17:32 Policy AllowUnsignedInstallationPackages = 110/07/2011 17:17:32 Policy AllowInternetSharing = 110/07/2011 17:17:32 Policy AllowPOPIMAPEmail = 110/07/2011 17:17:32 Policy AllowConsumerEmail = 110/07/2011 17:17:32 Policy AllowBrowser = 1
If any of these 0's or 1's is different than above, you may not sync.
The MFE Client writes the following line to admin.log (located under the folder MailForExchange on the Phone memory) when there is a policy that can’t be enforced:
Warning: Some unsupported server policies were found -- syncing may fail.
Note! You might receive a message to change to the manual sync when roaming on the Nokia Belle devices.
In the cases identified above, not being allowed to sync is expected behavior.
General information about policies: http://technet.microsoft.com/en-us/library/bb123484.aspx .