@floreean
Sorry just saw this ticket – You are seeing that issue because your host server is running an outdated and unsupported PHP Version? Probably version 5.5+ but it could be older – this is very bad.
PHP stopped support for 5.5 in July 2016 and they (PHP) strongly recommend that it is not used due to security vulnerabilities – see here
http://php.net/eol.php
WordPress Requirements state that to run WordPress system config should be
PHP version 7.2 or greater
MySQL version 5.6 or greater OR MariaDB version 10.0 or greater
HTTPS support
You can read more about that here https://ww.wp.xz.cn/about/requirements/
On that WordPress link there is a sample email that you can use to send to your host to upgrade your system. As soon as you upgrade to PHP 5.6 or higher you will not have the issue and your server will be much more secure.
Regards
Steve