No more working

Hello,

I’d suggest deleting the plugin entirely, making sure this line is removed from your wp-config.php file and try again:

if( !defined('WPMU_PLUGIN_DIR') ) define( 'WPMU_PLUGIN_DIR', dirname(__FILE__).'/wp-content/wp-safe-mode' ); //WP Safe Mode

There is no such or similar line in my wp config.
After istalling again I see an alert:

WP Safe Mode could not automatically install the required loader file. Please visit the WP Safe Mode Settings page for further instructions.

And then:

WP Safe Mode loader file installatiaon was cancelled. The following errors were produced during the last attempt to install the WP Safe Mode loader file, which would prevent your site from loading :

There has been a critical error on your website.

That means that some sort of plugin is preventing our plugin from safely installing itself, so it aborted not to crash your site.

I’m aware of the force-strong-passwords plugin which gets installed sometimes into wp-content/mu-plugins folder, that plugin just won’t work with ours, unfortunately, due to how it’s coded. You’d need to temporarily remove it to use ours.

I just wonder that it already has worked for few days.
I now have to switch to health plugin again.
Thank you.

Chances are you updated or added a new plugin or theme, and/or updated WordPress itself, and something combined is creating an error whilst WPSF is trying to load itself.

Try setting WP_DEBUG to true on wp-config.php and see what the error provided is, can you paste it here?

Ok, Thank You!