You need to understand their workflow and suggest friction free interfaces to migrate to a process that helps you too. This issue can be with any User & softwar

You need to understand their workflow and suggest friction free interfaces to migrate to a process that helps you too. This issue can be with any User & software combo not just a PM. If you can't get through UAT/UA (User Acceptance Testing/ User Adoption) then no matter how perfect a solution you make, it's irrelevant.