Data Gateway to on premise SQL Server Costs

Hello,

So I was working with a customer that stated they were using Power BI and connecting to onprem SQL through a gateway and it stopped working. They were told it was a license issue. Based on what I hear from them I believe its a problem with there datasource on the gateway where the creds don't have perms to the SQL server. Since I'm not a Power BI expert, I wanted to confirm if customers need to bump up their license to Power BI Premium to access data from their SQL server on prem. Their users all have Power BI Pro. Looking at this doc https://powerbi.microsoft.com/en-us/pricing/#powerbi-comparison-table  it seems that might be the case based on the line item "On-premises reporting through Power BI Report Server". Clear as mud. 

Customer comments.

"

We had set it up several years ago and it worked fine but it stopped before our last engagement with you guys.

At that time we were told that we needed a license but we would be temporarily licensed.

That temporary fix has apparently ended.

We are looking for a permanent fix.  Now we see this. 

This report couldn’t access the data source.

I re ran it locally and it worked.

I published it and when I went online I got the error.

"