Requests with big payloads not reaching our servers

[developing]

Since today morning some requests with big payloads don’t reach our servers, we have multiple domain with multiple distinct servers and I was able to replicate the problem in at least three domains, I’m unable to replicate the issue all the time, but now and them it occours, also some of our costumers seem to have the issue more frequently than what I was able to replicate.

Basically if I try to send a request where the payload is bigger than 300kb (at least from my analyzes) there is a chance (seems to happen randomlly) that the request will get stuck and never reaches our server, as far as I can tell the request seems to get stuck somewhere between the user’s browser and our server, the main and biggest service we have in this middle is Cloudflare, can someone help me to diagnose this clearly?

I’m not sure if this might help but I will also provide the cf-ray for the last failed requests:
6fb49232fdc4da76-LIS
6fb49239ad37da76-LIS
6fb4923f5c51da76-LIS

The main website were I’m able to replicate the issue is swonkie.com

Thanks in advance.

[jnperamo]

What error code did the requests get?

[leo11]

We’re experiencing a similar same issue for the LIS server: large uploads (bigger than ~1MB) more often than note produce an unexpected timeout message from CF When we point our hosts directly to our ELB bypassing CF, all works fine.

[developing]

The error code is 524, but the request never reaches our apache logs, we have targeted the upload to a blank script and the small files finish with 200 code, but the large files never reaches the server and we get 524 on browser network logs.