[Solved] http error 503. the service is unavailable iis

Follow the steps:

Steps 1: Open IIS Manager (short command: inetmgr) with Administrator Authentication


Step 2: Open the Application Pools node underneath the machine node. Select the Application Pool you want to change to run under an automatically generated Application Pool Identity. Here I’m selecting ‘Your Application Name’ Application Pool.



Step 3: Now right click on the selected Application Pool and click on ‘Advance Settings’ option.




Now here you have to set Start Automatically property ‘true’ and set Identity property is ‘ApplicationPoolIdentity’.


Now click button ‘Ok’, your configuration setting will be saved.


Reference from : http://www.mindstick.com