Hi Freddy,
are you running your Moodle instance on PHP 7.2.0? Are the sessions managed not via the default option (file system)?
It could look like MDL-60951 and https://bugs.php.net/bug.php?id=75628
I cannot find any ref in https://bitnami.com/stack/moodle about how Bitnami packages Moodle but if you're running Moodle on PHP 7.2.0 and using something different from the default file based session, I'd change the configuration of your Moodle sessions back to the file system option.
BTW, if the SEO Company has changed your PHP configuration - which is my actual guess - you should revert those changes and ask them to do the same thing in another way.
HTH,
Matteo