DocuSign error: ANCHOR_TAG_PROCESSING_FAILURE nodeJS

When I try to send multiple documents I see this error:

DocuSign error: ANCHOR_TAG_PROCESSING_FAILURE

But with one document it works fine.

My Code:

for (let i = 1; i <= envelopeArgs.docPaths.length; i++) {
  // console.log("envelopeArgs.docPaths[i]", envelopeArgs.docPaths[i]);
  let index = i - 1;
  const docPath = envelopeArgs.docPaths[index];
  console.log("docPath", docPath);
  let docFullName = path.basename(docPath);
  let docName = path.parse(docFullName).name;
  let docExtension = path.extname(docFullName);
  docExtension = docExtension.slice(1);
  let docBytes = fs.readFileSync(docPath);
  let docB64 = Buffer.from(docBytes).toString("base64");
  let doc = new docuSign.Document.constructFromObject({
    documentBase64: docB64,
    name: docName, //"fileToSign",
    fileExtension: docExtension, //"pdf",
    documentId: i.toString(),
  });
  env.documents.push(doc);
}
console.log("env.documents", env.documents);

This error usually means that DocuSign cannot read the documents that you sent over in order to find text matching your anchor strings. Reasons may be that the document is corrupt, password protected, or is encrypted in some form that prevents DocuSign from reading the text inside of it. The document may be visible to the signer, but not being read by the logic that supposed to match text and place tags using anchor strings, hence the error - ANCHOR_TAG_PROCESSING_FAILURE