What's the net::ERR_HTTP2_PROTOCOL_ERROR about?

Question

I\'m currently working on a website, which triggers a net::ERR_HTTP2_PROTOCOL_ERROR 200 error on Google Chrome. I\'m not sure exactly what can provoke this erro

Answer 1

net::ERR_HTTP2_COMPRESSION_ERROR - WORDPRESS

Okay, I hope this will help many. I have been experiencing this for many weeks. My apology because I am using WordPress.

net::ERR_HTTP2_COMPRESSION_ERROR only occurs on Chrome:Incognito.

I have Cloudflare for my CDN and caching HTML - and W3 Total Cache - for minify js, css and Page Cache, OP-Cache, Object Cache, Browser Cache.

now, after countless of trouble shooting, I detected the issue when disabling the "Browser Cache" after that, I fixed the problem when

I modified the Browser Cache ( go to side panel )

find the ("HTTP Strict Transport Security policy") make sure its checked. under that is directive set the value to - max-age=EXPIRES_SECONDS; includeSubDomain: preload

take note that I am using sub-domain.

Answer 2

I have been experiencing this problem for the last week now as I've been trying to send DELETE requests to my PHP server through AJAX. I recently upgraded my hosting plan where I now have an SSL Certificate on my host which stores the PHP and JS files. Since adding an SSL Certificate I no longer experience this issue. Hoping this helps with this strange error.

Answer 3

I am finally able to solve this error after researching some things I thought is causing the error for 24 errors. I visited all the pages across the web. And I am happy to say that I have found the solution. If you are using NGINX, then set gzip to off and add proxy_max_temp_file_size 0; in the server block like I have shown below.

 server {
  ...
  ...
  gzip off;
  proxy_max_temp_file_size 0;
  location / {
    proxy_pass http://127.0.0.1:3000/;
  ....

Why? Because what actually happening was all the contents were being compressed twice and we don't want that, right?!

Answer 4

We experienced this problem on pages with long Base64 strings. The problem occurs because we use CloudFlare.

Details: https://community.cloudflare.com/t/err-http2-protocol-error/119619.

Key section from the forum post:

After further testing on Incognito tabs on multiple browsers, then doing the changes on the code from a BASE64 to a real .png image, the issue never happened again, in ANY browser. The .png had around 500kb before becoming a base64,so CloudFlare has issues with huge lines of text on same line (since base64 is a long string) as a proxy between the domain and the heroku. As mentioned before, directly hitting Heroku url also never happened the issue.

The temporary hack is to disable HTTP/2 on CloudFlare.

Hope someone else can produce a better solution that doesn't require disabling HTTP/2 on CloudFlare.

Answer 5

I got the same issue (asp, c# - HttpPostedFileBase) when posting a file that was larger than 1MB (even though application doesn't have any limitation for file size), for me the simplification of model class helped. If you got this issue, try to remove some parts of the model, and see if it will help in any way. Sounds strange, but worked for me.

Answer 6

I didn't figure out what exactly was happening, but I found a solution.

The CDN feature of OVH was the culprit. I had it installed on my host service but disabled for my domain because I didn't need it.

Somehow, when I enable it, everything works.

I think it forces Apache to use the HTTP2 protocol, but what I don't understand is that there indeed was an HTTP2 mention in each of my headers, which I presume means the server was answering using the right protocol.

So the solution for my very particular case was to enable the CDN option on all concerned domains.

If anyone understands better what could have happened here, feel free to share explanations.