Batch request to Microsoft Graph returns "message": "Url specified is invalid."

{
  requests: [
        {
      id: '01GNYB5KKIKZVLU4SXJZAI6PD76QD3PUVQ',
      method: 'GET',
      url: 'https://graph.microsoft.com/v1.0/sites/bpmgroup.sharepoint.com,23e7ef7a-a529-4dde-81ba-67afb4f44401,0fa8e0f7-1c76-4ad0-9b6e-a485f9bfd63c/drive/items/01GNYB5KKIKZVLU4SXJZAI6PD76QD3PUVQ/thumbnails?select=large'        
        },
        {
      id: '01GNYB5KNZCQTFLFPNQNCJZXQVQWIBQWLG',
      method: 'GET',
      url: 'https://graph.microsoft.com/v1.0/sites/bpmgroup.sharepoint.com,23e7ef7a-a529-4dde-81ba-67afb4f44401,0fa8e0f7-1c76-4ad0-9b6e-a485f9bfd63c/drive/items/01GNYB5KNZCQTFLFPNQNCJZXQVQWIBQWLG/thumbnails?select=large'        
        }
    ]
}

Above is the batchPayload (testing with only 2 items) passed to my callMsGraph(token, batchUrl, batchPayload) function. And below is the received batchResponse:

{
    "responses": [
        {
            "id": "01GNYB5KNZCQTFLFPNQNCJZXQVQWIBQWLG",
            "status": 400,
            "headers": {
                "Content-Type": "application/json"
            },
            "body": {
                "error": {
                    "code": "BadRequest",
                    "message": "Url specified is invalid.",
                    "innerError": {
                        "date": "2023-05-17T18:17:39",
                        "request-id": "7bb48670-f436-4c16-8137-9d70abe92dab",
                        "client-request-id": "7bb48670-f436-4c16-8137-9d70abe92dab"
                    }
                }
            }
        },
        {
            "id": "01GNYB5KKIKZVLU4SXJZAI6PD76QD3PUVQ",
            "status": 400,
            "headers": {
                "Content-Type": "application/json"
            },
            "body": {
                "error": {
                    "code": "BadRequest",
                    "message": "Url specified is invalid.",
                    "innerError": {
                        "date": "2023-05-17T18:17:39",
                        "request-id": "7bb48670-f436-4c16-8137-9d70abe92dab",
                        "client-request-id": "7bb48670-f436-4c16-8137-9d70abe92dab"
                    }
                }
            }
        }
    ]
}

I have tested the urls as individual GET requests in postman, and they are indeed valid. But the POST response to batchUrl https://graph.microsoft.com/v1.0/$batch is returning that they are invalid?

I don't see how the URL could be malformed in anyway. I initially called each URL separately (without batching) with callMsGraph(accessToken, graphEndpoint) and the responses were fine -- the URLs are unchanged. I ofcourse want to utilize batching to reduce individual network requests.

My callMsGraph:

function callMsGraph(accessToken, graphEndpoint, payload) {
    const headers = new Headers();
    const bearer = `Bearer ${accessToken}`;

    headers.append("Authorization", bearer);
    headers.append("Content-Type", "application/json");

    const options = {
        method: "POST",
        headers: headers,
        body: JSON.stringify(payload)
    };

    return fetch(graphEndpoint, options)
        .then(response => response.json())
    ....
    ...

In a batch request you URL's should be relative https://learn.microsoft.com/en-us/graph/json-batching

> Required. The relative resource URL the individual request would typically be sent to. Therefore, while the absolute URL is https://graph.microsoft.com/v1.0/users, this url is /users.

so something like

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<!-- language: lang-html -->

{
  requests: [
        {
      id: '01GNYB5KKIKZVLU4SXJZAI6PD76QD3PUVQ',
      method: 'GET',
      url: '/sites/bpmgroup.sharepoint.com,23e7ef7a-a529-4dde-81ba-67afb4f44401,0fa8e0f7-1c76-4ad0-9b6e-a485f9bfd63c/drive/items/01GNYB5KKIKZVLU4SXJZAI6PD76QD3PUVQ/thumbnails?select=large'        
        },
        {
      id: '01GNYB5KNZCQTFLFPNQNCJZXQVQWIBQWLG',
      method: 'GET',
      url: '/sites/bpmgroup.sharepoint.com,23e7ef7a-a529-4dde-81ba-67afb4f44401,0fa8e0f7-1c76-4ad0-9b6e-a485f9bfd63c/drive/items/01GNYB5KNZCQTFLFPNQNCJZXQVQWIBQWLG/thumbnails?select=large'        
        }
    ]
}

<!-- end snippet -->