Testing that the server works
ManicTime Server is now up an running. If you open a browser on the machine where it is installed and go to (port might differ)
you should see the server's login screen.
Firewalls and routers
Now make sure that it is visible to other machines. On some other device, open a browser and try to go to the server. You will probably have to write an IP of the server's machine
If this does not work, then ManicTime client also won't work. Usually the problem is firewall or router. If you have a firewall, make sure that it allows connections to the server.
Same thing if you have a router. You need to allow incoming connections (port forwarding) to the server.
Before you try to connect in ManicTime, always first try to make the connection from a browser.