Staging site no longer accessible (replaced by WP install page)

Hi there!
After having implemented without any problem a staging site with your plugin and having done many site’s updates (during two days), this morning (the third day), I cannot access anymore to my staging site (front and backaend): my site displays the WP install page (/wp-admin/install.php) as if the database doesn’t exist anymore !! : (((
I tried to look at the debug-log-mode (as described in your page (https://wp-staging.com/docs/enable-wordpress-debug-log-mode/) but I don’t have any error corresponding to this event (last one dated oct 1st).
How could you help me to identify what’s going?
Will I lose all my updates if I install again my db (as required)?
What could I do to revover my staging ste?
Thank you for your prompt and kind answer
CGC

The page I need help with: [log in to see the link]