Err appears in Google browser_SSL_PROTOCOL_ERROR

under test http://localhost:8080/ The following error occurred during

This web site cannot provide a secure connection. Localhost sent an invalid response err_SSL_PROTOCOL_ERROR

At this time, you need to open a blank page for input chrome://net-internals/#hsts
Find the delete domain policy
at the bottom of the left navigation bar. It has a delete domain security policies
example picture

then enter localhost in the domain input box and press Delete
and you’re done!

PS: this method is only for learning and use, and the user shall bear any legal disputes and consequences