Zoho Bigin connection from Flow

Hi,

We have created a Flow which uses a webhook to receive data from a form. The data includes a Bigin dealid and dealname. That part works fine, as we can see the data in the flow and we also tested sending data to the webhook using Postman.

Then, we have tried updating or fetching a Deal from Bigin using this data, but it always fails. The error we are getting when testing the flow or in the Flow History is:

Bigin says "Please check if the URL trying to access is a correct one"

The connection between Flow and Bigin supposedly works fine. We also tried creating a new connection, same problem.

Is there are problem with fetching data from Bigin, or are missing something? Our Flows with other Zoho apps as well as a Bigin to Zoho Sheets flow work fine.