I have configured a data gateway on my clients dev server. I have configured the gateway power bi and it says it is ok. When I try to map my dataset to the gateway under the "schedule refresh" option in Power BI I keep getting an error, I have included the screen shot of the error and am a bit lost on how to proceed at this point.
If you have not done so already, I would suggest registering the data source(s) within your Power BI Gateway.
Setting<Datasets<Gateway connections<Manage Gateway<
Here you can add more data sources to your registered gateway. Make sure the credentials match what you used for the data gateway and for others who want to refresh you mark them as a "User" in data source settings pane.
Make sure your account used by the gateway has the correct permissions to the underlying data sources as well.
I hope that helps!
A bit late to the party but just wanted to thank @cosborn1231 for proposing this.
My gateway was missing one of the 14 different datasources my PBI report is pulling, and I couldn't figure out why I was getting error 400. Guess MS needs to work on these error messages.