Go to cpanel/ ftp, plugins folder, delete the plugin, reload the website.
If you want to speed up your website, develop a theme from scratch, plugins make website vulnerable and bulky. Use optimized images, less in disk space and high in quality.
Disable all plugins and check the response somehow cache plugin conflict with one of theme plugin
Set permalink structure
Clear cache of your site through the plugin
just for cross-checking test another cache plugin
Once you check all the above points and found no luck so it must be your theme development issue than check your hooks which you have used in your theme development.
2
Answers
Go to cpanel/ ftp, plugins folder, delete the plugin, reload the website.
If you want to speed up your website, develop a theme from scratch, plugins make website vulnerable and bulky. Use optimized images, less in disk space and high in quality.
There are several reasons for that:
Once you check all the above points and found no luck so it must be your theme development issue than check your hooks which you have used in your theme development.