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 is thrown by server so you have to check if SharePoint services are running.
Cause can be change in to identity account or password or in most cases password expire.etc.
Please follow following one of the solution to sort out the error and get back to your share point site.
1) Ensure that the enable32BitAppOnWin64 setting for the “SharePoint Central Administration” app pool is set to False, and the same for the “SharePoint Web Services Root” app pool
2) Edit applicationHost.config:
FilesMicrosoft SharedWeb Server
Central Administration v4″ />
SharedWeb Server Extensions14isapiowssvr.dll” preCondition=
“appPoolName=SharePoint Central Administration v4,bitness64” />
1. Go to IIS Manager (Start > Administrative Tools > Internet Information Services Manager)
2. Expand the server node, and Click on Application Pools
3. Locate the Application Pool of the SharePoint site, If it is stopped – Start it. click on Advance Settings
4. Click on the right of the Identity box to change it (A window will pop up).
5. Click on Set and simply retype your App Pool Identity in there with the new password.
For the sake of testing, you can select “Predefined” and select local service from the drop down.
Create Service accounts with never expire password, May this works fine too.
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.