Cannot activate the plugin

Hi there – you’ll find the same issue here – https://ww.wp.xz.cn/support/topic/php-error-message-20?replies=7

But I see that you say your version is 5.4.24, but I know that the plugin works on that version.

I would double check with your host, or see if there are any PHP settings in your cpanel that you can change or verify the version.

Otherwise if it is an older PHP version and the host provider won’t change the PHP version you can still use the older SlickNav version.