I mentioned a problem that we were having in crediting and reinvoicing a service order in another thread, and then I discovered that this was the problem.
We have restricted all users access to cancel invoices (we have specific users who need to create credit memos in specific ways, so we don’t want them to use this shortcut). As a result of this, the ability to “Add Return Line” has also automatically been restricted. See below. The orange should be restricted, the green should be allowed:
