Data Gateway query

Hello,

I have a separate data gateway created for a on premise SQL server and Oracle database. I also have a dataflow created by Admin and granted with access (not sure about source type).

If I am creating a PowerBI report based on on-premise SQL server the schedule refresh works.

If I am creating a PowerBI report based on Oracle database the schedule refresh works.

If I am creating a PowerBI report based on Dataflow the schedule refresh works.

Currently I have got a requirement from client where I need to merge data based on on-premise sql server, oracle database, PowerBI dataflow and a sharepoint data. I have created report in PowerBI desktop but when I try shedule refresh it doesn't happen and throws error as below.

I think I am not able to select individual data gateway for each source and for sharepoint my own credentials. I was thinking to create a separate PowerBI dataflow for Oracle and on-premise sql server where I can connect individual data gateway. Finally I can connect all these in PowerBI desktop and no gateway is required at this point. I can do schedule refresh easily. 

Is this a good solution that I am going to follow or what went wrong?

Thanks,

Karthik