@theertha Padman I also ran into this issue
I am using the current NPM SDK (v3.0.0) to access FormRecognizer, which targets the service API v2.0
However when reading the docs here: https://learn.microsoft.com/en-us/azure/cognitive-services/form-recognizer/quickstarts/label-tool?tabs=v2-0 I found that there are two links with the same text (FOTT Website) but each has a different link value - this is where things went wrong for me:
I was using the first one which is v2.1 (preview) so my API calls were failing expecting models trained using v2.0
I switched to the non-preview FOTT Tool which is v2.0 and my API calls began working just fine (although the recognition accuracy drops off notably in v2.0)
All the best!