Erreur d'installation ou d'activation - erreur d'analyse : erreur de syntaxe, T_FUNCTION inattendue

The T_FUNCTION error usually occurs when an unsupported version of PHP is installed on the server. MemberMouse requires PHP 7.4 to operate correctly, and you’ll have to talk to your hosting provider to see if they support that. This article contains more information about the issue and what to look for when resolving it: Fin du support pour les versions de PHP antérieures à 7.4

Once you’ve figured this out with your host, then you should be able to follow the install steps (found here for your reference: Installation de MemberMouse) et installez, activez et mettez en route votre nouveau site d'adhésion.