I am using Lightsail server installed Bitnami WP - my site is getting not reachable , I need to reboot or stop and start instance. then its working

Hi,

You may need a upgrade your instance to a larger plan for your website. You can use the below doc to help investigate your cpu performance and determine if you need a larger plan.

https://lightsail.aws.amazon.com/ls/docs/en_us/articles/amazon-lightsail-viewing-instance-burst-capacity