editor shows nothing after change

[llagos]

Hi. I've encountered this problem many times before, where I modify something, and click on refresh, just to get a blank screen as response. Usually I close the browsers (I try on both, Edge and Chrome), and the problem is fixed, it shows the diagram, no problem.
Today, it's with the same problem again, but this time, I just can't get it to "wake up". Tried 2 browsers, closing and reopening, even reboot my laptop... Still a blank screen.
It's not syntax error (those show up)...
I use .com URL since .DEV also does nothing when I press ctrl-Enter.
Any help?
Thanks,