Fix : "Service Unavailable" Errors..

[eUK-Gabriel]

You may face this error message with ASP.Net 2.0 or higher version sites.
Restarting the IIS should fix this error as it recycles the application pools on server.
Following are some reasons and resolutions if restarting IIS does not fix this error :

1] Application pool of the web site is crashed / not running

Verify that the application pool is configured for the domain, and its running with following steps -

On your server Click Start >> Programs >> Administrative Tools >> Internet Information Services (IIS) Manager >> Expand ServerName >> expand Web Sites >> here locate the domain name in question >> right click the domain name and select Properties >> Click on Home Directory tab >> here in front of "Application pool" in drop down box you will get the application pool of this web site.

Now again in IIS expand "Application Pools" >> locate the application pool of web site and check its status, [Status may be Stopped or Running] >> if its stopped then right click on application pool and select Start.

2] Application pool account / user have incorrect password

In IIS expand Application Pools >> right click on application pool of the domain >> Properties >> click on Identity tab >> here type in password in Password box and hit Ok >> in Confirmation pop up box reenter the password and hit Ok.

3] Application pool account is not a member of IIS_WPG group (IIS Worker Process Group)

On your server Click Start >> Programs >> Administrative Tools >> Computer Management >> Expand Local Users and Groups >> Users >> locate and right click on account used by application pool >> Properties >> here click on Member of tab >> confirm that IIS_WPG listed in the Member of list, if not then add IIS_WPG group.