Android Skype for Business issue with Exchange iApp

I did the debug but still not able to get to the bottom of it. If the EWS auth is set to Basic+NTLM I see this in the logs: ~~~ 2016-04-27 19:23:59 /Common/exchange_external:Common:aed70e0a: Following rule 'Successful' from item 'NTLM Auth Result' to item 'SSO Credential Mapping' 2016-04-27 19:23:59 /Common/exchange_external:Common:aed70e0a: CREDENTIAL MAPPING agent: Master encrypt failed, null plain password ~~~ If it is set to Basic, the logs look normal, but the Android agent still gives the error message that it can't connect to server.