Error bad getway when open node-red

I add the node-red when I open it I receive error bad getaway, see attached picture.
I didn’t find any understand way how to fix that.
I have also the Advanced SSH & Web Terminal, it’s the same problem when I try open it, I don’t really know if I need it, but the error is the same.
How know how can I fix it?

Stop and start the addon, give it a minute go to the log page, click refresh. Wait 10 sec refresh again. Do this until it starts/crashes post the results. Also when/if it loads go back to the start page of the addon click open web ui.

I stop/start like your suggest
I check the error log, I ahve a problem with the port that in use
I change the port to another, it’s working