Hello! Thanks for using my addon! The previous user that had this issue wrote me this:

I managed to fix the issue. It was just change the web address on preferences to webk.telegram.org and them I went back to web.telegram.org and the the button on extensions bar worked as well as before.

I work on that but for now that's a workaround.

If not, feel free to write me down to alejandrosbrizuela [at] gmail [dot] com.