Thank you Leon,
as you said, that setting wasn't right in my site, although the line to correct the parameter was in my php.ini and it had worked in previous versions of my Moodle installation.
Actually, the problem was in that php.ini. It used hash signs for comments, which was allowed previous to PHP 7.0. When I migrated to this new version of Moodle, it also required me to upgrade my PHP version... which happens not to accept # and so it broke my php.ini file.
Thanks a lot for your help :D
as you said, that setting wasn't right in my site, although the line to correct the parameter was in my php.ini and it had worked in previous versions of my Moodle installation.
Actually, the problem was in that php.ini. It used hash signs for comments, which was allowed previous to PHP 7.0. When I migrated to this new version of Moodle, it also required me to upgrade my PHP version... which happens not to accept # and so it broke my php.ini file.
Thanks a lot for your help :D