So I’ve found this bug in the MineOS Web UI where it doesn’t allow you to create a server (error is that the user isn’t in the group it’s being created under) however the user is in that specific group. I’ve done research on it but no real solutions. Well, I’ve found the solution to that problem. When creating a user, it’s uaually in 1 primary group with no secondaries, where the problem doesn’t occur (such as in the default mc username and group). But when using multiple groups, you will bump into this problem, unless you add the group twice. For example you create a user with the name as que123 with the primary group of test, and secondary of root and mc. Now you goto the UI and login as that user, then try creating a server in the group test, you will be greeted with that error. The only way to fix it is to have test listed as secondary also.
Summary: If you create a user with multiple groups, you cannot create a server in the primary group unless that primary group is also listed as a secondary group.