URGENT - XFDF Merge API giving [500] internal server error

Which product are you using?

PDF.js Express Plus

PDF.js Express Version
v8.7.0

Detailed description of issue
There is an issue with the merge function provided by @pdftron/pdfjs-express-utils.
Some users, using chrome & edge browsers are getting 500 Internal server errors while our web app uses the merge function which results in a PDFExprress API call of /merge.

Hi PDF JS Express team,
I’m writing given an unexplainable 500 error we are receiving with a small set of users. We can’t figure out if it’s our error or a bug with PDF JS Express software. We’ve now had a few users report this issue — can you please help us debug it?

I’m attached a few screenshots and will try to explain the issue. After the PDF form load inline (with annotations filled in) — and we go to “Save” the form, we’re receiving a 500 “merge” error. The details are attached below — showing a more detailed message saying “server-side request must use server-side key.”
Please let us know how this can be resolved.

Issue

Expected behaviour
The merge function leads to the PDFExprress API call of /merge to work on all client’s chrome browsers.

Does your issue happen with every document, or just one?
Only some of the users are facing this issue, same form/pdf is working for other users.

Link to document

Code snippet

/**
   * Returns file for edited PDF.
   * @returns {Blob}
   */
  async getPdfFileData() {
    const { documentViewer, annotationManager } = this.webViewer.Core;
    const utils = new ExpressUtils(PDFJS_EXPRESS_UTIL_OPTIONS);

    const xfdf = await annotationManager.exportAnnotations({});
    const fileData = await documentViewer.getDocument().getFileData({});

    const resp = await utils.setFile(fileData).setXFDF(xfdf).merge();

    const mergedBlob = await resp.getBlob();

    return mergedBlob;
  }

Screenshots:





Is it possible that some of the users are using a proxy?

Best Regards,
Zach Serviss
Platform Support Engineer
PDFTron Systems, Inc.

Hi,
We are experiencing this same issue for users with network proxies. Wondering if there’s any way to work around the issue to avoid forcing users to eliminate the proxy.
Thanks