I received a notification about their production account credentials (AccountNo, LicenseKey and WebService URL). Reviewing the "Edit System Control File Record" the only place to add the new web service URL was in the section "HTTP User Headers and Data" section. Adding the new web service URL to this section produced an "ActionNotSupported" fault code.
The message with Action 'https://avatax.avalara.net/services/GetTax' cannot be processed at the receiver, due to a ContractFilter mismatch at the EndpointDispatcher. This may be because of either a contract mismatch (mismatched Actions between sender and receiver) or a binding/security mismatch between the sender and the receiver. Check that sender and receiver have the same contract and the same binding (including security requirements, e.g. Message, Transport, None)
Avatax SDK for IBM i
The only requirement to change the web service URL from Development to Production is to set the boolean property "Is this a Production Account" setting on the "Edit System Control File Record"( AC001R1) to "Y"
Modifying the SOAPAction statements will result in the error fault error experienced. They should be left as they are.