How to catch WiFi connection with login page?

Question

Java

There is a certain open network. When connected to it, the user opens the login page on the local network in the browser. Also, the login page supports passing parameters with a POST request.

How everything is implemented at the moment:
1. The user scans a QR code
2. The application creates a connection to the desired WiFi network.
3. The device connects to the network.

But on some devices, a problem got out - network connection events are not caught.
The problem showed up on Samsung Galaxy S8 and did not show up on Oppo realme, both on Android 9.0.
I use CONNECTIVITY_CHANGE as an event.

How would you advise to catch the establishment of a connection to the waffle?