Does anyone know about this error message when submitting SO: "The Sales Orders account cannot be used with the XXXXX subsidiary." I checked the Customer and Item and they adhere to the subsidiary. I turned off all the UE scripts and WF yet error persists.

Non-posting transactions still get a GL impact and there's a non-posting GL account called Sales Orders that gets associated with SOs. Sounds like you just need to ensure that account is available to the sub you're trying to save the SO to.

you nailed it, thank you.