WPMUDEV Dashboard not showing up and can't upgrade Appointment+

I cannot see my WPMUDEV Dashboard, which is one problem. However, my main problem is that I cannot upgrade my Appointment+ plugin.

When I select it as a plugin from network admin I see the following message: There is a new version of Appointments+ available on WPMU DEV. View version 1.5.5 details. However there is no upgrade now link. Please help.