Data Domain File Library Credential Issue

Hi All

We have a DP 8.1 Install (Win2012R2) configured to back up to file library devices.

These devices are being presented over CIFS from a Data Domain.

Our backups are consisiently failing .. with a 'Unauthorized access, username or password' incorrect warning in the session messages.

We have confired that the  DD excepts connections from any client, the NTFS permissions look fine, the INET service looks okay ... Are we missing something fundamental here or could anyone offer any suggestions?

Many thanks in advance.