Hi Paloma,
I don't know why it does not work but so far it seems a Chrome issue only. On my PC diagrams, as I typed this, were visible again in Chrome, but were not. (Edit: Now they are gone again...) Edge has no issues. On Android, Chrome still does not work as you also report. But Firefox does work on your phone probably too
Debugging is twice as hard as writing the code in the first
place. Therefore, if you write the code as cleverly as possible, you
are, by definition, not smart enough to debug it.
-- Brian W. Kernighan
In Playstore there was an update for Chrome available. I restarted the telephone OS (so you have to log in again on Android) after installing the update to clear cache etc. I don't know if they changed something but here the diagrams are visible again. (Edit: Sigh... after refreshing the page the red textbox appeared and diagrams vanished again) For Windows there is not yet a new Chrome update to try as far as I can see.
Debugging is twice as hard as writing the code in the first
place. Therefore, if you write the code as cleverly as possible, you
are, by definition, not smart enough to debug it.
-- Brian W. Kernighan