Passing along a tidbit regarding wifi security settings. I’ve had a Chromecast for some time that I had not been able to get set up on my home wifi. It turned out that the issue was the encryption setting in my Apple TimeCapsule. I had selected WPA/WPA2 Personal rather than the WPA2 Personal setting. I ran across a StackOverflow article saying that switching to WPA2 Personal would fix the issue. I made the change and the Chromecast started working right away. Making the change did not affect anything else (so far) on my wifi.