What does this error message mean?

Hello friends!

I just want to know what the error message mean?
My HTML5 project wont start

Press CTRL + SHIFT I
Then go to the console to see if there are any more information on the issue.

this is looking like a general error we are seeing with HTML5 on UE4.21… i am unfortunately not able to repro this exact error anymore. but i will be looking into similar errors i am seeing currently.

UE 4.21.0 seems to be a little more stable for HTML5 – while 4.21.1 just seems to be all kinds of broken for HTML5.

apologies, i’m trying to get a fix on this.

the following AH is something more what i’m running into currently:

i will be continuing my responses there…