Tag: nginx error

Nginx upstream sent too big header
When I log in to a PrestaShop website, I get an error on a Plesk server.
```
502 Bad Gateway
```
On checking error login for the site in folder /var/www/vhosts/domain.com/logs/proxy_error_log, I found the following error message

proxy_error_log:2020/11/25 19:41:41 [error] 1809#0: *39664 upstream sent too big header while reading response header from upstream, client: 59.92.71.53, server: tulivesi.com, request: “POST /en/login?back=my-account HTTP/2.0”, upstream: “https://shop.serverok.in:7081/en/login?back=my-account”, host: “shop.serverok.in”, referrer: “https://shop.serverok.in/en/login?back=my-account”

To fix, add the following to Nginx config.

If Nginx works as a reverse proxy to another application server.
```
proxy_buffer_size          128k;
proxy_buffers              4 256k;
proxy_busy_buffers_size    256k;
```
If Nginx serve pages using FastCGI/fpm.
```
fastcgi_buffers 16 16k; 
fastcgi_buffer_size 32k;
```
On Plesk Server

On Plesk, go to the domain name, then click “Apache & nginx Settings”. On next page add the following code and click OK.
```
proxy_buffer_size          128k;
proxy_buffers              4 256k;
proxy_busy_buffers_size    256k;
```
See Nginx
November 25, 2020
Nginx HTTP 414 request-URI too large
On a Nginx server, when accessing a long url, i get error
```
HTTP 414 Request-URI Too Large
```
To fix the error, edit
```
vi /etc/nginx/nginx.conf
```
inside “http” section, find
```
large_client_header_buffers
```
Replace the line with
```
large_client_header_buffers 4 32k;
```
If your URL is very large, you may need to increase the 32k to higher or reduce the url length.

Large url like this mostly happend due to bad application design, so if possible try to make URL smaller.

Restart nginx
```
systemctl restart nginx
```
On older servers (centos 6, ubuntu 14, etc..), run
```
service nginx restart
```
See Apache 414 Request-URI Too Long, Nginx
February 6, 2020

Tag: nginx error

Nginx upstream sent too big header

On Plesk Server

Nginx HTTP 414 request-URI too large