Connecting to what speaker? Does this speaker have its WiFi turned on? How do you know it isn’t connecting? How is your Sonos system connected to your LAN? What device is your controller on? Which version of the Sonos OS are you on? What router are you using?

Why did you do the reset? That causes so many folks so much grief.

Maybe power down all Sonos. Reboot your router. Power up only the Sonos you want to connect the Sub to. Power up the Sub. Use the Controller’s Add to System tool to add the Sub back in.

Finally got it to connect, after doing a rest, it wanted to pair with everything in the house- different amps and sound bars- but not with the home theater basement soundbar that I wanted.  Finally, it showed up as an option and I’m back in business. 

somebody unplugged a few things that created the problem.  D

Just as a reminder, the Sub can only be connected in one Sonos ‘room’ at a time. To change ‘rooms’, you need to unbend it from the current ‘room’, then add it to the new ‘room’.