Error de instalación o activación - error de análisis sintáctico: error de sintaxis, T_FUNCTION inesperada

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 de soporte para versiones de PHP anteriores a la 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: Instalación de MemberMouse) e instalar, activar y estar en camino a su nuevo sitio de membresía.