Ethereum-boilerplate: The ultimate full-stack

I have entered this link ( ) after I encountered the youtube awesome video

but unfortunately, the tutorial does not reflect reality. everything is easy in the video but right in the beginning I have seen lots of problems

for example

Error: A cross-origin error was thrown. React doesn’t have access to the actual error object in development. See for more information.

i tried to look search via google and other but no luck