Hi @YinXun,
Yep, this sounds like maybe you just have too many processes running and emperor can't load (it takes a fair amount of resources). Shut down other processes or restart your computer and try again. Please give that a try before proceeding.
Alternatively, if you recently updated your browser another issue could be afoot. Check out these related topics — I don't think they describe the same issue you are seeing, but they are possible explanations to explore if my theory does not pan out: