I connected to my hotspot on my phone but it took two tries, the first didn't work. The message saying it didn't work won't go away and i can't even shut down. Help

I tried connecting to my phones hotspot and the first time it didn't connect. I tried again and it worked fine but the message saying it didn't work was still there. After a day it is still there and my computer even died and when it charged again the message was still there. My computer won't allow me to shut down or restart because i can't close the system preferences. What do I do?