When running a SmartConnect map with a Xero destination, receiving an error that says “Failed to import XXX – Xero API returned error http code: ServiceUnavailable” This seems to happen after 60 documents. If the map is run again, it seems to process 60 more, and then returns the same error message.
The Xero API limits you to 60 inserts in a single session. If you have more than 60 inserts to make, you will have to break the data source into multiple sets of 60 records.