I have a Libray that we built a workflow on, and the workflow exists according to SharePoint, i.e. you can start it manually from a document, but the Nintex workflow app no longer see's the workflow so we can't edit it

We built a few workflows using Nintex on a document library and suddenly - Nintex no longer identifies the any of the workflows - although if you go into workflow settings they are displayed through SharePoint, and if you navigate to workflows via the ellipsis on a document, you can manually launch the workflows.

But we can not edit them.

The Nintex Workflow app shows up in the site contents, but not on the ribbon, when I launch it, there are no workflows to edit.  - see screen shots in the attached word file.

How do I get Nintex to recognize the workflows again so we can work on them?