Preview does not finish the loading bar and screen is all in black

recently I had the problem with internet because I used the develop cloud type of project so as my internet wasn’t good it does not load but now I am using it as a project in my computer and does not load, I have connect to good internet to see if it is the problem but still don’t load, it stays like this:

It never changes and I do not know what to do
pls help

Either press ctrl + shift + i, or select hamburger (in the top left) > Vew > Toggle Developer Tools


Preview it again, and see what errors crop up.