wifi not connecting to mac air or TV

My MacBook suddenly stopped connecting  to my home wifi, repeatedly saying it needs a wpa2 password. Additionally, on my tv, it shows up and I put the password in, it states they are unable to connect.

All other devices still connect to home wifi and the Mac happily connects to any other wifi network. Also when  trying to connect to just the Xfinity wifi hotspot on the home router it reports ‘unable to join this network’. Apple have done a complete software check (remotely) and confirmed all is working as it should. Can anybody help me with this odd issue ?