I have noticed a weird behavior regarding POST requests on all my servers from devices that are connected to the internet either via 4G or via hotspot from a 4G network.
I am an admin of 2 services hosted at AWS. Both services use the same Elastic Load Balancer and are hosted via ECS (docker). Both services run with gunicorn and django but listen on different endpoints.
The thing is that ALL of the POST requests made from a device with a 4G or a hotspot connection never ever seem to even reach the ELB (according to the logs no request is recorded), which is the first entry point that I control.
I used debug mode and tried some requests from my Android device and I can see from the Chrome dev tools Network tab that the request silently fails with no response code. It just stalls.
I can freely copy the request as curl and it works.
The JS code is nothing fancy, a typical AJAX POST request.
Any ideas as to what is going on? Any tips as to how to debug this?