If you get this page after logging in Zoho and confirming permissions instead of being redirected back to the Customer Shell Portal.
Check the CRM domain selected for the integration, it needs to be in the correct region, you can check the region by opening the CRM and checking the URL
Allow Ringotel IPs in your Zoho Account
If your Zoho account is IP restricted, you will need to add the following Ringotel IPs in your Zoho Accounts portal (accounts.zoho.com) → Security → Allowed IP Addresses:
54.145.196.146, 18.130.161.112, 3.0.222.77