Settings > Permalinks – mod_rewrite ineffective if expression not preceded by /index.php/
SOLVED: This is Apache2 on Debian: added the following to the ./sites-available/wp_container.conf virtual hosts file. Note that AllowOverride must be placed inside <Directory …> … Include conf-available/rewrite.conf <Directory /var/www/html/wp_container/> AllowOverride All </Directory> …