Gateway data source works for one Office365 Account but not for another

[wilson_smyth]

I have an Office 365 account with PowerBI Pro, lets call it Acc365_A.
Using this account i  installed the Pn Premises gateway.

I was then able to set up a gateway & data source that connects to a tabular cube on my internal LAN & importing data works. All good so far.

I created a second office 365 account called Acc365_B.

I first grated this account admin privileges on the gateway and tried to Import data. 
I select SQL Server Analysis Services >MyDataSource. I expect to see the database name but i get the eror "login failed for user".

As the gateway simply passes the login username and password from the gateway to the database, and both 365 accounts are using the same gateway, i dont know why i can import data from this datasource for Acc_A but not for Acc_B.

[wilson_smyth · Accepted solution]

Update, I got this sorted.

It seems the original account i set up the gateway with was mapped already to a local user. The 2nd account, Acc_B was not and so was getting a failed login.

I had to "Map User Names" for Acc_B and map it to the local LAN account.

Not sure why I didint have to do this with the Acc_A, but at least i have an avenue for investigation.