During your sync operation, you receive an error which says ‘Internal Error. Details are available in Magento log file. Report ID: webapi-“XXXX”‘ in the target application, which is Magento 2.

Cause

One of reasons for this error:
 Unknown as Magento error logs are not returned from the source application.

Resolution

To resolve this issue, follow the links below for reference.
How to check Internal Error Details are available in Magento log file