Did you mean only this one user have the access issue to this app workspace?
Was the app workspace old version or new preview version?
Was this user a internal user or external user?
If this user is a internal user, the workspace should be available in Workspaces tab as long as the user has permission. Please let this user check if the app workpsace is listed on Workspaces tab.
this workspace was created in December 2018 and the users has been able to access it. For some rease the workspace called Publishing is no longer visible for him. He is an internal user and belongs to our domain. there are 14 other users that are abe to see and use the publishing workspace. I have logged in using the users credentials and do not see the workspace publishing?
I am still struggling with this problem, it has now gone to the point when i create a new user account i get the same message of "Sorry you don't have access to that group"