Phone is connected to wifi but internet not working

Hello. Yesterday my mother's phone (a motorola Moto C) received a software update notification. We updated it and it was very light with no major changes (about 51 Mb), and everything is working okay, except for the wifi connection. It connects to the wifi but there's no internet (i tried connecting to 2 different wifi networks and it happens with both of them). This is everything i've tried so far:

• I turned off and on the wifi on the phone (also i put it in plane mode).

• I unpluged the power of the router, then i waited for a while, turned off the phone. Then I turned on the router and the phone.

• I tried changing to IP configuration to static.

• I did a network settings reset.

• I deleted the cache.

• I even did a Factory data reset.

None of these has worked so far. Any ideas to solve this? I'm sure it has nothing to do with hardware, since the only difference between the working and not-working states is the update.

The phone worked well. I suppose i has to do with the update but i don't know if it is possible to go back to a previous version.