Q: MBook doesn't see my wireless

First off, I'm sorry for posting here, I didn't see any forum options for my setup. I am running a MacBook Air with the beta of Sierra OS 10.12.

My husband can get on our main wireless connection fine, on his MacBook Pro. I have a MacBook Air, and a Airport Capsule for backups, with its own wireless.  My computer isn't seeing the main one and moves me to the Capsule wireless. I can live with that, but don't know why this is happening.

Any help is appreciated, thanks.