am facing an issue with field mapping between Zoho Books and Zoho CRM.

I want to map the GST Registration Number field from the Customer module in Zoho Books to a custom GST field inside the Accounts module in Zoho CRM.
However, I am getting a warning message saying:

“We’re unable to fetch data from some of the mapped fields.”

This issue is shown in the first screenshot below.
📎 Screenshot 1: Sync configuration error (Unable to fetch mapped fields)

Additionally, as shown in the second screenshot, when I try selecting the GST field mapping, it shows an error with a red mark ❌.

📎 Screenshot 2: GST field mapping error

Also, the synchronization process between Zoho Books and CRM takes a long time whenever a new customer is added. It shows “Import is in progress” for a long period.

Could you please guide me on:

1️⃣ Correctly mapping GST Registration Number to the CRM Accounts module
2️⃣ Resolving the “unable to fetch mapped fields” error
3️⃣ Reducing sync delay between Zoho Books and CRM

Any help or suggestions would be greatly appreciated!
Thank you!