The Authorization Endpoint and Token Endpoint URLs should be DC-specific. Hence, if you are trying to add a Zoho One account in one Data Centre (DC) to a Microsoft Entra ID account in another DC, you have to change the DC in the URL.
For example, if your Zoho One account is in India, you have to change the .com value in the URLs to .in (like this
https://accounts.zoho.com/oauth/v2/token to https://accounts.zoho.in/oauth/v2/token).