BrowserSync is a useful tool to improve your web development workflow, but occasionally it may not function properly. In such cases, the first thing to check is the normality of the source code.
For example, if the source code has been rewritten in an unintended form for some reason, such as a cat stepping on the keyboard, BrowserSync will not function. In particular, if the first part of the HTML is like ” ;k<!DOCTYPE html>'', the browser cannot recognize it as a normal HTML document, and BrowserSync will not function properly.
Therefore, when BrowserSync does not work, first check the source code to see if any unintended characters are mixed in.