Please make sure that your device is connected to the DSL router via LAN cable and not via Wi-Fi. If you experience problems even when connected via LAN cable, it may be due to the video call system you are using. I can recommend Google Duo.
@Sonali What kind of router you use? I have fear an o2 homebox. If it is an o2 Homebox try different names for the 2.4 and 5 GHz Wifi.
Thanks Joe, Blablup, I use Homebox. I will check with LAN Cable but still does not solve the issue, then it will be a router problem. If that works.
@Joe, how to choose different GHz, from laptop/mobile itself or do I need to change some configuration in Router?
.
@Sonali if you have with lan cable problems, please raise a technical ticket. Change the WiFi names you will do it the o2 Homebox.