Most webmasters face this problem sooner or later. The rankings of your website on Google have dropped and you don’t know why this happened.
There are many reasons about rankings on Google can drop:
Reason 1: Your server rejects Google’s spider
Have you installed a new robots.txt file lately? Does your robots.txt file allow Google to index your website? Have you changed your htaccess file? Have you recently installed a spam bot blocker?
Are you 100% sure that the spam bot blocker lets Google through to your website? Google uses different IP addresses for its different spiders and some spam blockers might accidentally block one of the spiders. This might also look like cloaking to Google.