We have instances where the service node throws ResolverError. This happens for a service node that is using password grant type Oauth2.
The weird thing here is, if we create a separate service node to get a token, then pass it to the other service node, it is working fine. Another thing, is that if the API returns 200 or 201, it succesfully processes the service node as shown below.
We can share a sample bot if it can help in the investigation.