Julia 1.10.2 + IJulia + ubuntu mate 22.04 = blank page

two days ago I installed ubuntu mate 22.04 (=last LTS) on my PC together with julia 10.2
I installed the IJulia package as usual (add IJulia) but now when I open julia in a terminal,

using IJulia

as I’ve always done, the browser (firefox) opens but displays just a blank screen, with
as the address in the address bar. No listing of folder, files… none whatsoever.

Do you know if there is a way to recover the jupyter notebooks?

Please notice that

using IJulia

does indeed work, showing the address

On a second topic, I’ve seen (not in my new machine) that jupyter now appears
with this new and ugly interface that I don’t like much. Do you know if it is possible
to revert to the previous interface?

Thanks a lot,