Site crashed after installing recommend plugin.

Hi i have a problem, i get “Parse error: syntax error, unexpected ‘/public_html/wp-content/object-cache.php on line 336” after i followed the advice to install the Redis cache plugin, i found out my php version is to old and i don’t know if that cause the problem… at the same time i installed defender and wanted to run it, but it crashed… i can’t acces my site now, admin or frontpage…

i’ve sent an email with my FTP details.