Why my website s IIS pool is crashing ?

If you receive an HTTP Error 503 message, it is highly that your IIS application pool has stopped in server.

• If your website is consuming a high amount of CPU resources in server ,which could impact the performance of your server. In order to protect the stability of the server, the website was recycled (restarted) in server. During the recycle process, you will receive Service Unavailable in your site, however, the website will reactivate itself shortly.

• If your website has hard-crashed multiple times in rapid succession which has triggered Rapid Fail Protection. Rapid Fail Protection is a feature in IIS that will monitors your website for hard-crashes, and if a certain number of errors occurs in a certain amount of period, it will deactivate the website in server.
  

• If the website hard-errors more than times in short period, this indicates that the website is most likely malfunctioning in server and will need to be manually reactivated the IIS for the site in server.

• If you are receiving the Service Unavailable error because of high CPU utilization. Optimise your application which causing the CPU spike or hard-crashes.

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