Access to the provided image was forbidden using batchUpdate of Google Docs REST API

I'm using Google Docs REST API batchUpdate to replace images in a Docs file. When I first created the code, I had a permission error and I saw a couple of posts that actually solved this:

1. https://stackoverflow.com/questions/63309338/using-google-docs-api-to-insert-image-from-google-drive
2. https://stackoverflow.com/questions/70311191/access-to-the-provided-image-was-forbidden-even-though-it-was-uploaded-from-the

This has been working, but for some reason after some time I get the same error even though nothing has changed. The image I used is still shared publicly (Anyone with the link).

I need to use a service account for this one.

The error I get:

error={message=Invalid requests[12].replaceImage: Access to the provided image was forbidden., code=400.0, status=INVALID_ARGUMENT}

My code snippet:

function postGoogleAPI(url, payload){
  var service = getOAuthService();
  service.reset();


  var response = UrlFetchApp.fetch(url, {
    method: "POST",
    contentType : "application/json",
    headers: {
      Authorization: 'Bearer ' + service.getAccessToken() // a function that gets the access token
    },
    payload: JSON.stringify(payload),
    muteHttpExceptions: true
  });

  return JSON.parse(response);
}

function getGoogleAPI(url) {
  var service = getOAuthService();
  service.reset();

  var response = UrlFetchApp.fetch(url, {
    headers: {
      Authorization: 'Bearer ' + service.getAccessToken() // a function that gets the access token
    },
    muteHttpExceptions: true
  });

  return response;

}


function getReplaceImageRequest(imageFileId, docsFileId, mergeField) {
  let requestData = [];

  let url = Utilities.formatString("https://www.googleapis.com/drive/v3/files/%s?supportsAllDrives=true&fields=webContentLink", imageFileId);
  let response = getGoogleAPI(url);

  let logoUri = JSON.parse(response).webContentLink

  url = Utilities.formatString("https://docs.googleapis.com/v1/documents/%s?fields=inlineObjects", docsFileId);
  response = getGoogleAPI(url);

  let inlineObjects = JSON.parse(response.getContentText()); 

  for(const key in inlineObjects.inlineObjects){
    let title = inlineObjects.inlineObjects[key].inlineObjectProperties.embeddedObject.title;

    if(title != null && title == mergeField){
      requestData.push({
        "replaceImage": {
          "imageObjectId": key,
          "uri": logoUri,
          "imageReplaceMethod": "CENTER_CROP"
        }
      });
    }

  }

  return requestData;
}

getReplaceImageRequest(<id of image file>, <Docs file id>, <identifier of merge field>);

let url = "https://docs.googleapis.com/v1/documents/<id of Docs file>:batchUpdate";
let payload = {
    "requests" : requests
  }
  
let response = postGoogleAPI(url, payload); // Error occurs here

I've tried manually resetting the general access type with no success. If I upload a new image, it works though.

So in summary, the code works until for some reason the image is not accessible anymore, even with access type still set to 'Anyone with the link'.

I hope anyone can help here, thanks in advance!

I think I solved the problem, at least my update has not failed so far. The problem was in the code that gets the link of the image (/?supportsAllDrives=true&fields=webContentLink). I changed it to /?supportsAllDrives=true&fields=thumbnailLink and this works so far. So for some reason the webContentLink field value changes after some time, and results in the error I encountered.