How do I change the credentials for a Dataflow pulling from a SQL server behind a gateway

Hi all,

So I've got a issue. I have a dataflow which I created that pulls data from two databases in a SQL server behind a gateway. When I initially created the dataflow I didn't use one of the service accounts to connect to the server.

Now I want to change that connection credential as I'm getting errors using my own credentials as opposed to the service account but I cannot find anywhere in the dataflow that allows me to manage credentails.

I checked the dataflow settings area but under the credentials area I can't update credentials because apparently admin has granted access.

Which is strange because it was giving me an error saying I can't connect to it.

So I then tried to create a new dataflow using the basic connection and entered the service account credentials. It all loaded in the Power Query editor in Power BI service but when I go to refresh the data it's throwing the following error:

Error: Data source credentials are missing or invalid. Please update the credentials for SQL in dataflow settings and try again. 

So in the end I've got 2 questions:

1. How to I update credentials for an existing Dataflow

2. If it's not possible what could be causing the refresh error for a duplicate data flow I've created with updated credentials.