Zoho oAuth complains about response_type parameter

Zoho oAuth complains about response_type parameter

Hello,
For the last two weeks we have been trying to reach your team regarding the following issue.
As seen in the screenshot below, we are rejected by the Zoho oAuth with the following error:
"Response type Allowed values are code and token". But as you can see by the url, we are already asking for a code with the correct parameter.

This same exact method was working before until it started to not to. We didn't change our code. What is going on?