Fix SuitePOS Error: Unexpected Error Null on Transactions | SuiteRetail Support
NetSuite Script Error: Error getting the transaction - UNEXPECTED_ERROR null
This happens when you try to retrieve a transaction (server side) and the transaction has not been written to the server yet. This can happen when retrieving a sales order or when you are trying to do an "on-demand" search.
Please wait a while and when the transaction is written, you should be able to retrieve it.