What does ERR_SPDY_PROTOCOL_ERROR mean in nginx?

Question

I and a few of my colleagues got the net::ERR_SPDY_PROTOCOL_ERROR error.

We use ngnix version 1.8.0. The error is not stable (hard to replicate), and t

Answer 1

For me it was Nginx configuration that didn't allow OPTIONS method. I had whitelisted GET|PUT|POST|DELETE only, so when Chrome tried to send OPTIONS method, for God knows why**, the error was reproduced.

Open up Firefox and repeat the request, then look at the Network inspector to check if any OPTIONS requests are being sent.

** probably to check for X-Frame-Options or HSTS verification.