Google play InAppProduct API get returns 400

Question

I'm doing a server-side validation of the purchase made via the android app. For this, I need to make 2 calls

1. purchases.subscriptions.get
2. inappproducts.get

The 1st call to the purchase subscription API is successful whereas the 2nd call to the in-app products API fails. It was working fine until yesterday and started failing all of a sudden

Can someone please let me know what the next steps are? I found this thread which talks about the exact same issue but it's almost 7-8 years old and I see no conclusion on it. Looks like this could be a bug on the Google's end but I'm not sure

Any help is greatly appreciated

Here's the error I'm getting from the API

{
  "code" : 400,
  "errors" : [ {
    "domain" : "global",
    "message" : "Non-existent in-app product",
    "reason" : "badRequest"
  } ],
  "message" : "Non-existent in-app product",
  "status" : "INVALID_ARGUMENT"
}