You need to login with your GitHub account to access the private repo. You can invite yourself here: https://aspnetzero.com/LicenseManagement
You can implement your own method and get all clients by _onlineclientmanager.GetAllClients();
You can override UserManager's IsGranted method regardless of whether MultiTenancy is enabled.
For ABP version, right-click on solution and select "Manage NuGet Packages".
For ASP.NET Zero version, check for these changes made in specific versions:
Which ABP version and ASP.NET Zero version is this?
As mentioned, try clearing your browser cache (and cookies).
Try clearing your browser cache.
I have not encountered that. But you can safely remove those entries from your database.