My pc devices get set to ipv6 and cant connect to most websites

[cptmajere]

Today out of nowhere all of my PC/laptop devices lost internet connection. I reset the modem but afterwards my mobile devices started getting internet and connection but my pc devices didn't. Also my pc's can't connect to the modem interface. I connected from mobile and saw my pc's are getting ipv6 assigned only. I followed  tobiastheebe   's answer from a previous post:

Can you temporarily set a static IPv4 configuration on the PC (example below)? This should allow internet access via IPv4 again and you should also be able to reach the modem's web interface ( 192.168.178.1 ). I'm curious what the Advanced Settings → DHCP page says there.

IP address: 192.168.178.2
Subnet Mask: 255.255.255.0
Gateway: 192.168.178.1
DNS Primary: 1.1.1.1
DNS secondary: 8.8.8.8

And it started working afterwards. I can connect to the modem and everywhere But I want to get to the bottom of this. Can you help?
 

[tobiastheebe]

I have sent you a private message in reply to yours.

[cptmajere · Accepted solution]

If anybody else is experiencing this problem, with the help of Tobias I have solved it by power-cycle'ing the modem (plugging off the power input from the moment for 2-3 minutes). I will update if I learn more.