Q: Keychain Issues: Office 365 in Open Directory

We're having keychain troubles with Microsoft Office 365 in a Open Directory configuration, using an Apple Mac Mini with Apple El Capitan as server. Somehow we can't get Microsoft Office 365 products (Word, Outlook, Powerpoint, Excel) to activate, getting the following error message:

"Error raised: 11. Additional Information: Domain: ADAuthenticationErrorDomain ProtocolCode:(null) Details:Cannot add a new item in the keychain. Error code: 100001."

We've already informed Microsoft about the problem, but until now they don't know how to solve the issue. Does anyone knows a solution for the problem above?

Thanks in advance.