@BenediktB while your there, before supplying the key, lets teach one more valuable thing…
with the mirror running, using a keyboard, hit ctrl-shift-i, a new window (the developers window) will open.
select the tab at the top labeled ‘console’ and then scroll up to see any errors, usually in red…
you can also get messages from JUST ONE module, by putting part of its name in the filter box, on the console tab, ‘weath’, hit enter
u can close that window with the same keystrokes, or using a mouse hit the x in the top right corner
u can start the dev window at start time too with npm start dev