If you have an SSAS cube and you setup a gateway data source then go to User Mapping and switch the radio button to CustomData, the connection string used is now: [email protected];C...
Let's say I register the gateway data source with username VM1\admin and then turn on CustomData in the user mappings. The actual connection string used to connect is when logged into Power BI as [email protected]: EffectiveUserName=VM1\admin;[email protected] So the issue is that if VM1 is not domain joined, then EffectiveUserName=VM1\admin will fail since that's only supported against domain accounts. So this appears to be a Power BI gateway bug that needs to be fixed so that it doesn't specify EffectiveUserName in the connection string when CustomData is on.
