Uploads to my website stall if using cloudflare reverse proxy

[macksix]

I already talked to technical support at the datacenter and they have no answers.

I have a dedicated server on HiVelocity.com that hosts a social media site. I had no problems before, but recently when making a photo or video post on the site, the uploads will stall. If the file is small, it will stall a bit and then I am able to post, but if it is a larger file, it stalls and will not complete.

A 2mb mp4 upload will never complete.

If the Cloudflare reverse proxy is turned off, the website works normally and fast.

Here is a video showing the problem. I have to wait for about 2 min. and then it fails. If I immediately refresh after the fail, it shows a 520 error. Recording #18

Normally, as soon as the blue progress bar finishes, the file is uploaded and I can post.

See video of posting the same with Cloudflare reverse proxy off: Recording #19

This is a test site, not the production site.

[fritex]

@macksix

a photo or video

@macksix

but if it is a larger file, it stalls and will not complete.

Larger than 100MB?
How much time does the request need to upload it, less or more than 100 seconds?

Is your origin host / server configured via PHP (if you are using PHP web app?) to accept file uploads w/ other PHP settings, like for example as follows below:

upload_max_filesize = 32M
post_max_size = 64M
max_file_uploads = 20
max_input_vars = 6000
max_input_time = 1000
memory_limit = 256M
max_execution_time = 300

@macksix

A 2mb mp4 upload will never complete.

What does your Developer Console (F12) from your Web browser say? Any warnings or errors shown from like Ajax or JavaScript?

[macksix]

Larger than 100MB?

No, the failure occurs with only a 3MB mp4

How much time does the request need to upload it, less or more than 100 seconds?

The 3MB mp4 will upload in about 2 seconds without the Cloudflare reverse proxy turned on. With the Reverse Proxy turned on, a 520 error is thrown in about 90 seconds.

Is your origin host / server configured via PHP (if you are using PHP web app?) to accept file uploads w/ other PHP settings, like for example as follows below:

My php.ini:

display_errors = Off
max_execution_time = 600
max_input_time = 600
max_input_vars = 2000
memory_limit = 512M
post_max_size = 140M
session.gc_maxlifetime = 1440
session.save_path = "/var/cpanel/php/sessions/ea-php74"
upload_max_filesize = 128M
zlib.output_compression = Off

What does your Developer Console (F12) from your Web browser say? Any warnings or errors shown from like Ajax or JavaScript?

Yes, see screenshot.

This is what causes the web application (php, javascript, css, mariadb) to drop down a general “something went wrong” error message.

[fritex]

@macksix

screenshot

From the provided screenshot, I see you do get Error 520 on the HTTP POST request.

May I ask have you already looked into the 520 error about suggestions?

• https://support.cloudflare.com/hc/en-us/articles/115003011431-Troubleshooting-Cloudflare-5XX-errors#520error

Community Tip - Fixing Error 520: Web server is returning an unknown error

Error Try the suggestions in this Community Tip to help you fix “Error 520: Web server is returning an unknown error”. Background Error 520 is essentially a catch-all response when something unexpected happens or when the origin server incorrectly interprets or does not tolerate a request due to a protocol violation or an empty response. A 520 error occurs when the connection started on the origin web server, but that the request was not completed. The most common reason why this would occur …

Before moving to Cloudflare, was your Website working over HTTPS connection?

May I ask what SSL option have you got selected under the SSL/TLS tab at Cloudflare dashboard for your domain ( Flexible, Full, Full Strict … )?

Here is a way to re-check if you correctly setup the SSL for your domain with Cloudflare:

Deprecated - Step 2: Setting up SSL with Cloudflare

This tutorial is deprecated in favour of Get started with SSL/TLS · Cloudflare SSL/TLS docs

Archive

This tutorial covers getting SSL working with Cloudflare in various different scenarios. This assumes you already have your website set up on Cloudflare with all your DNS records set to , if not - please visit <a href="https://community.cloudflare.com/t/64309">Step 1</a>. Do you want the website to use HTTPS? Yes Do you already have a valid SSL certificate installed…

In case you do not have an SSL certificate, you can use Cloudflare SSL, if so, kindly make sure you follow the instructions as follows on the below article to setup an SSL certificate using Cloudflare Origin CA Certificate:

• Origin CA certificates · Cloudflare SSL/TLS docs

Last but not least, kindly have a look here for more information regarding correct SSL settings at the SSL/TLS tab on Cloudflare dashboard:

Why you should choose Full Strict, and only Full Strict

Unencrypted & unverified connections Imagine you open Paypal and suddenly get that warning [image] Would you continue? Probably not. For decades leaders in IT security have advocated that people upgrade their sites from unencrypted HTTP to secure HTTPS. And for a reason, everything you send via an HTTP connection is sent in plain text and can be intercepted at any point between you and the server. Equally, you’d probably not proceed if you got such a warning, right? [image] That’s when th…

Furthermore, do not skip below step and kindly re-check if Cloudflare is allowed to connect to your origin host to as follows in the below article:

• https://support.cloudflare.com/hc/en-us/articles/201897700-Allowing-Cloudflare-IP-addresses

Nevertheless, Cloudflare IP addresses list can be found here:

• IP Ranges

[macksix]

@fritex

From the provided screenshot, I see you do get Error 520 on the HTTP POST request.

May I ask have you already looked into the 520 error about suggestions?

• https://support.cloudflare.com/hc/en-us/articles/115003011431-Troubleshooting-Cloudflare-5XX-errors#520error

I asked HiVelocity tech about it and they asked Cpanel about it and they both said they have no idea why it happens. I have not looked at these personally, since it worked before and it works fine with the reverse proxy turned off. I will look into these myself:

• Headers exceeding 16 KB (typically due to too many cookies)
• An empty response from the origin web server that lacks an HTTP status code or response body
• Missing response headers or origin web server not returning proper HTTP error responses

@fritex

Before moving to Cloudflare, was your Website working over HTTPS connection?

Yes it works fine on SSL now with Cloudflare reverse proxy turned off or turned on. I have a SSL cert on the server too.

@fritex

May I ask what SSL option have you got selected under the SSL/TLS tab at Cloudflare dashboard for your domain ( Flexible, Full, Full Strict … )?

It’s set to FULL.

@fritex

Furthermore, do not skip below step and kindly re-check if Cloudflare is allowed to connect to your origin host to as follows in the below article:

• https://support.cloudflare.com/hc/en-us/articles/201897700-Allowing-Cloudflare-IP-addresses

HiVelocity techs said we only needed to allowlist IPs in firewall, which I have always done. I double checked them against the Cloudflare IP list and they are all there. I will still look into this more.

File uploads are not completely blocked with reverse proxy on, only files over 2mb won’t upload. Files under 2mb upload OK, but they are delayed and are slow to finish, while without the reverse proxy, uploads under 2mb will fully upload in less than 2 seconds for me.

Thanks!