Troubleshoot errors in Calendar Interoperability
To verify if Calendar Interoperability has been set up correctly, you can perform tests using Free/Busy lookup tester provided in the Zoho Mail Admin Console. The details of the error, if any, are shown in the Exchange Configuration page. 
Under Calendar, navigate to the Advanced Settings > Reports > Calendar activity tab to view the details of the configuration/test performed.
Below are troubleshooting tips for common issues:
| Issue | Cause | Resolution/Fix |
| No response received from Exchange server | Connection between Zoho Calendar and Microsoft Exchange server is not established successfully. Possible reasons include: 1. A firewall might block the connectivity between both the servers. 2. Incorrect entry of the hostname or port. | Ensure that the Exchange server is connected to the internet. You can use the Microsoft Remote Connectivity Analyser tool to check if the Exchange server is accessible from the internet. Make sure to spell-check the intended hostname or port. |
| SSL Handshake exception | SSL certificate is required while trying to set up internet connectivity in Calendar Interoperability. The SSL Handshake exception error occurs if:
| While entering the hostname, double-check if the name matches the one in the SSL certificate. Also, check if your SSL certificate license is still valid and then proceed. |
| Unable to Resolve Email Address | This error typically means the entered email address does not exist or is incorrect in the respective server (Exchange). | Double-check and ensure the email address entered during the configuration is valid and exists in the server's directory. |
| Availability config command not supported | Verify whether the organization customization is enabled for the particular user account. | Run Enable-OrganizationCustomization command in the powershell. |
Add-AvailabilityAddressSpace: ||Active Directory operation failed Directory object not found | Check whether the account being used is an Active Directory account to run the setup. | Run the command New-AvailabilityConfig in the powershell to create a new availability address space. |
| Command not found | Verify the management roles required for the command to run. | Run the following command: Get-ManagementRole -cmdlet Get-AvailabilityConfig to verify the management role required for the command to run. |
| Check whether the user has sufficient management role required to run the command. | Run the below command to verify the management role of the particular user. Get-ManagementRoleAssignment -RoleAssignee <user@domain> | |
| Organization configuration role not present. | The user account is not provided with organization configuration role. | Add the required role to the user's account by running the below command: New-ManagementRoleAssignment -Role "Organization Configuration" -User <user@domain> |
| Federated Sharing role not present. | The user account is not provided with federated sharing role. | Add the required role to the user's account by running the below command: New-ManagementRoleAssignment -Role "Federated Sharing" -User <user@domain> |
By following these steps, you can diagnose and resolve common errors during the setup of Calendar Interoperability in Zoho Mail for Microsoft Exchange calendar.