Why does a mobile phone connected to WiFi not see the router, while the Internet is working?

Question

Android

There is a Wi-Fi router, it has been working for many years, everything works fine from the TV and the old phone to the new ones.
I bought a Xiaomi Redmi 5A (7.1.2) phone, connected wi-fi, checked the Internet speed 46/45Mbps, everything works, no questions asked.
But then I ran into a problem that despite the fact that the phone receives the Internet from the router, I don’t see it, i.e. I can't ping the router itself. I ping servers on the Internet, I ping devices in the local area, but I don’t ping the router itself!
All my other devices ping the router just fine.
I poked all the settings on the phone, deleted wi-fi, reset network settings - there is no result.
PS. How do you not want to do a factory reset.
P.S.S. I understand networks, so I can say that all the settings in the phone received via DHCP are correct, there is nothing to complain about :( I sin only on the internal settings of the phone.

Answer 1

Solved the problem though.
I have a Mikrotik router on Wi-Fi.
I tried to change the DNS address in the DHCP server, replaced the router's ip with 8.8.8.8 - it did not help.
I solved the problem in a trite way, I just prescribed to assign an ip-address in DHCP statically, and it all worked.
I don’t understand why the “dynamics” didn’t work with this particular gadget, there are no such problems with the rest. I can’t comment on who is to blame here, it seems like DHCP gave out the correct settings, and the phone received them, but it didn’t work.
Here is such an ambiguous decision. I wrote it because it might help someone. And then I already wanted to reflash the firmware on the custom phone. Although I may ask again, I don’t like a lot of things on the phone, but that’s another story.

Answer 2

What does "doesn't work" mean? What is it expressed in?
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