Why can't a mobile phone see the Internet via WiFi?

Question

Android

The situation is very strange: OnePlus, official firmware (out of the box), Android 11, optical Internet (PON network), router from the provider (ONT), that is, I did not configure anything, I did not raise bridges. I bought a new phone the other day, it connects to Wi-Fi, it even writes "There is a connection", the device is given an IP address, mask, etc., after a minute the status changes to "Connected, no Internet". At the same time, I immediately try to connect to sites (via the literal domain and IP address directly), the connection is not established, the browser thinks for a long time and nothing is loaded. But what is very strange and interesting: at the very first connection, notifications from Google services appeared, even updates began to be downloaded (but to no avail), an update from the manufacturer itself (firmware) came (by notification, but also to no avail), and some applications (from Google, the keyboard, for example) managed to send data (you can see it on the traffic monitor in the settings). It seems that the Internet appeared once, and then for some reason immediately disappeared>.

At first I thought that Wi-Fi was broken, but it happened, but not with me (I saw complaints from people) precisely because of the incorrect settings from the provider (he issues them via OLT) and simply because of failures. But the wire works. And on other devices too (including Android, but there is not version 11, really). I called the provider, they said that everything is fine and there is nothing they can do to help. Cool ... I rebooted the router, of course (even a couple of times), and the provider itself offered to reboot the equipment on its side, I agreed, but it didn’t help (although this is essentially just rebooting my router remotely).

And what to do, how to solve the problem?

Answer 1

Check the connection of the phone to other routers / access points. If it does not work - the factory defect of the phone or the curvature of its firmware. If it works with other devices, change the provider's router to something decent.

Answer 2

You can look for the reason in the phone settings or in the ONT settings that are not available to you, but

But the wire works.

Buy your access point, connect it by wire and configure it as you need.

Answer 3

Perhaps the problem is that the phone defines the network as public and waits for the registration confirmation form from the router.
I have come across similar.
Do you have an open network?