Service Unavailable: HTTP Error 503. The service is unavailable error normally occurs whenever the password for the application pool identity account is changed or application pools are in the stopped state. This error may appear temporarily when you deploy solutions. In my case, I realized that password got changed for the Identity account.
Here are the steps to resolve:
If you are running SharePoint in Windows 2003:
- Go to Start >> All Programs >> Administrative Tools >> Internet Information Services (IIS) Manager.
- Locate your App Pool account and right-click on it and select “Advanced Settings”.
- Go to process model then Identity Click on the Identity >> Set and then give the user name, password and confirm password.
Hope this will work fine after that.
Here is the Microsoft KEDB: https://support.microsoft.com/kb/823552
If you are running SharePoint in Windows 2008 or Later:
- Go to IIS Manager (Start > Administrative Tools > Internet Information Services Manager)
- Expand the server node, and click on Application Pools
- Locate the Application Pool of the SharePoint site, If it is stopped – Start it. If the password is changed, update the password:
It could happen when the App pool’s Advanced Property: Enable 32-Bit Applications is set to “True”! It should be false.
Tail: Application Pool Starting and Stopping? or Application Pools stops after restart? Make sure your application pool account has “Log on as batch job” rights!. This error may occur when necessary services like the World Wide Web Publishing service, SharePoint Timer Service is in the stopped state.