SyntaxError: Unexpected token < in JSON at position 0

[wshamroukh]

I am following your blog to try out your full stack application. I have tried all different front end applications, but when I try to login or sign up, I always get this error
SyntaxError: Unexpected token < in JSON at position 0
Using Devtools in the browser, I can see that we are always failing in this line in the main.js:

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