When using an old wifi router (wifi standard 4 or older) disturbances of Internet connection or even complete outages can occur. The problem for this is an increasing radio traffic in the 2.4 GHz range caused by other wifi networks, Bluetooth devices, Microwaves and the like.
As network provider we have no influence on this.
Therefore it is strongly recommended to switch to the 5 GHz range if possible.
The network service of the provider ends at the network socket in your room. For the wifi set up behind it, no functioning guarantee can be given.