Anyone else receiving the following message when attempting to edit a sales order

That means it has a transaction attached to it that you'd need to delete first. Could be an Item Fulfillment, Purchase Order, Credit Card Receipt, Invoice, Return Authorization, etc. If you delete those "child" transactions, it should let you delete the Sales Order.

Understood but I'm not actually trying to delete the order at all. I just need to update the order. When we reviewed the console log it's throwing a 500 error, which points to a network issue I believe. Waiting on NS support to "help"