Last week, Google's Cast-enabled devices (including the Chromecast streaming dongle) started crashing users' home wi-fi networks. Well now Google has released a fix, and it's as simple as downloading an app.
It comes in the form of a Google Play services update. It should automatically download to your device, but if it hasn't yet, you can download it here.
The problem arose because Android devices' Cast feature was beaming too much data at a very high speed in a short amount of time. This slowed down and even crashed wi-fi connections when you tried to beam TV, film or music content from a mobile device to a Chromecast dongle, Google Home smart speaker or Android TV.
Routers affected include those made by TP-Link, Asus, Linksys, Netgear and Synology.