Running NodeRED

I have installed NodeRED, but when I try to start it, the circle goes round for about 5 seconds, then it redisplays the box “NodeRED is not running - do you want to start it”. You can keep clicking the Start button over and over. How do I find out what is wrong?

Thank you - Rowan

Have you looked at the logs? They are usually a good place to start…

Either NodeRed is not running and the log tab in the top should show you why or NodeRed is actually running, but your browser is just pulling the page from its cache and that is the one showing not running.
If it is the browser, then a force refresh should solve that.