It shows no servers today, and says Master Server not responding.

Try run the game with +set sv_master1 [master.ioquake3.org](https://master.ioquake3.org) in the command line.

Thank you, do I just copy this into the ingame console: "+set sv_master1 master.ioquake3.org"? I tried it with the + and it didn't work, then I tried without and nothing happened.

I’m having the same problem

In the command line, not the console. ie: in a shortcut to the executable or in a batch file.

I can't find the command line, I have been googling for hours?

In Windows?

Create a shortcut, add that text to the end of the shortcut target.