Gateway Not Working - WHY?!

[FAY2020]

Can anyone tell me why this is not working?

All sources are mapped except for two SharePoint hosted Excel files which don't need to be. Yet it won't 'select' the gateway (fill in the little dot in the top left) and un-grey out the credentials and refresh schedule.

I have had this with other reports and deleting the dataset and republishing works, but I have a complicated Excel report hooked up to this dataset so that is definitely not an option.

[FAY2020 · Accepted solution]

So taking over the dataset on another account allowed me to configure the gateway there, not sure if I take it back to the original account what will happen, something about sleeping bears...