Certain Apps not working on WiFi

[Kj513]

We recently returned from vacation and came home to certain apps on iOS devices not working while on the WiFi.  We cannot access Gmail - it says no connection; FindMy will not locate; YouTube videos do not load; Facebook and Instagram say no service.   We have rebooted, checked with internet provider, and updated firmware.  Net gear tech support will only talk with us if I purchase additional warranty.   

[microchip8]

You don't say which router model.

You don't say its firmware version.

You don't say which modem/gateway it is connected to.

You don't say if you're using custom DNS.

You don't say which WiFi band (2.4/5 GHz).

How are we supposed to help?