I found a solution - sort of. I have added the mozilla ppa to my Ubuntu.

sudo add-apt-repository ppa:mozillateam/ppa sudo apt update sudo apt install thunderbird 

When thunderbird was updated to version 102.4.1, the extensions were working again.

I found a solution - sort of. I have added the mozilla ppa to my Ubuntu.

sudo add-apt-repository ppa:mozillateam/ppa sudo apt update sudo apt install thunderbird 

When thunderbird was updated to version 102.4.1, the extensions - and my calendar – were working again.