database connection loss

I have installed the plugin and can get to the settings, but once I get there, updating the settings, or updating pages is either very slow or I get a connection lost message.

I’ve tried deactivating all plugins except woo and the theme’s required “core” plugin, and the problem persists.

What php version does the plugin require?

https://ww.wp.xz.cn/plugins/woocommerce-currency-switcher/