Changed router now cannot add sub or set up Alexa on the soundbar

I changed broadband supplier to Sky from BT last week and have since struggled to get my Sonos system to work as before. 

Somehow I have managed to get the Beam and both SL1 speakers to work but the Sub is not being recognised so I cannot add it to the system. 

Also, I cannot get Alexa to work on the Beam, I try to add it as a voice assistant but when it asks me to log in to my Amazon account nothing happens. 

Any ideas gratefully received!