Connection timeout when 3+ devices from same ip/wifi

Hello, I’m having issues connectig to my server when there are 3 or more devices in the same network/wifi/ip trying to connect to my app.

This started on december 26 and i dont know what could be causing this issues.

Basically i have a PHP based CRM (espoCRM) and a ionic app.

The Ionic app connects to the server and the php - MySQL system via HTTP calls (API REST).
The app is used by several devices connected to the same wifi.
Before Dec 26 it worked perfectly but now i can only connect with 1/2 devices 3 or more i get connection timed out.

Any ideas whats going on? anny configuration or something im missing?

Sorry for bad english and thanks for the help.