Service Unavailable: HTTP Error 503. The service is unavailable in SharePoint

 

Service Unavailable: HTTP Error 503. The service is unavailable error normally occurs whenever the password for application pool identity account is changed or application pools are in stopped state. This error may appear temporarily when you deploy solutions. In my case, I realized that password got changed for the Identity account.

 

 

 

Go to IIS Manager (Start > Administrative Tools > Internet Information Services Manager)

Expand the server node, and Click on Application Pools

 go to app pool, right click , select advanced setting , click identify, change user name and password, click ok

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.

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 World Wide Web Publishing service, SharePoint Timer Service is in  stopped state

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