Resolving the 'The request has SAS authentication scheme.....' error message when querying SharePoint lists from Power Automate ...

The Problem

Came across this weird error message in Power Automate when running any simple Get Item, or Get Items, action against a particular SharePoint List:

The request has SAS authentication scheme, 'MSAuth1.0' authorization scheme or internal token scheme. Only one scheme should be used.

Puzzled the heck out of me.  Authorization?  Was looking at Auth Settings, creating new flows, testing - couldn't get to the bottom of it.

But - as usual - after a bit of digging got to the bottom of it and it was a red herring!  This was the error message coming back in the Get Item action:

{

  "status": 400,

  "message": "The query cannot be completed because the number of lookup columns it contains exceeds the lookup column threshold.\r\nclientRequestId: 35f6d637-91c3-47d4-9872-xxxxxxxxx\r\nserviceRequestId: 7bb7cba1-a00f-e000-1b2f-xxxxxxxxx"

}

The Cause

The actual problem was that the list in question used lots of lookup fields - around 20 - and this was the cause of the issue above!  Lists with more than 12 lookup fields can cause problems in Power Automate when retrieving data from the SharePoint list.

The solution?  Create a SharePoint View in the SharePoint List which has 12 or fewer lookup columns, then adjust the Get Item or Get Items action to utilise that view, e.g., 

The Result:

Yay! Mystery solved!