How to fix HTTP Error 503. The service is unavailable in Windows?

Error message

HTTP Error 503. The service is unavailable.

HTTP Error 503 Service Unavailable


In Windows hosting, this error occurs when an application pool for a particular website is stopped or crashed when website exceeds the private memory limit of 250 MB.

All websites hosted under our Windows shared server have its own dedicated application pool. By default, these application pools hold 250 MB of private memory, so your web application can use maximum 250 MB of private memory. If any web page/request that demands more than 250 MB of private memory, application pool of your website will get stopped/crashed and your website will throw HTTP Error 503. This event will be logged at the Web server logs.


This error can be fixed by manually starting the application pool from IIS itself. While you have purchased the Windows shared hosting, you wont have IIS access. Hence, if you face this error, you can contact us either through chat or ticket. After starting the application pool, if the same web request will come (that caused the application pool crash previously), you may face this error again. Hence, rather fixing it each time when you receive this error, we will send you the exact exception that caused the application pool crash so that you can fix your code to prevent its recurrence.
If your web application is really that heavy, and it demands more than 250 MB of private memory then you should consider purchasing additional application pool private memory. Additional 250 MB private memory will cost you $5 / Month. To purchase additional private memory, you can contact us through Helpdesk.

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