Unable to Modify Project User List

User has a project where we cannot add or remove any user. It complains about problems with the server connection. But S/R works fine for that project and we can add/remove users on the related Back Translation projects. Submitted problem report. PTXS-19584.

I verified user is one of two admins. Project is “Lohorung” (lhr).
I ran the advanced: “Verify Project Repositories” no issues found.