Get Changes for an item or file BadGateway Error

[NewToFlows]

I am new to PowerAutomate automated SharePoint flows. I have created two workflow to automate approvals for documents stored in our library. The first workflow for new files is working perfectly. There are different approvals for a revision of a document, and I am struggling on this second flow. I created a trigger for when a file is modified (this trigger works correctly) and then I want to get the changes for the document to see if the body of the file has changed (vs the metdata tags).  I am receiving a 502 Error Bad Gatway and I am not sure what I've done wrong.

[NewToFlows]

The errors I am getting are:

{

  "error": {

    "code": 502,

    "source": "unitedstates-002.azure-apim.net",

    "clientRequestId": "aca8c3d7-034a-4058-b748-beff57efbf1f",

    "message": "BadGateway",

    "innerError": {

      "status": 500,

      "message": "Index was out of range. Must be non-negative and less than the size of the collection.\r\nParameter name: index\r\nclientRequestId: aca8c3d7-034a-4058-b748-beff57efbf1f\r\nserviceRequestId: aca8c3d7-034a-4058-b748-beff57efbf1f"

    }

  }

}

[v-qiaqi-msft · Accepted solution]

Hi @NewToFlows,

I recommend you use the Sent HTTP request to SharePoint action instead to get previous version, there is a blog introduced how to use it, hope it could help you:

Check for a Change in a SharePoint List Column Val... - Power Platform Community (microsoft.com)

In addition, you could check your SharePoint list settings and see if the modified items are the issue to affect your version.