Description:I have hosted my Web Application in IIS 7.5. It was worked well for the past one or two months. But today, when I try connect my Web Application thorough URL I got the HTTP error page with the message HTTP Error 503. The service is unavailable.
Cause of HTTP Error 503. The service is unavailable:After I have analyzed some time, found the reason. The HTTP Error 503. The service is unavailable occurs if the Application Pool of the corresponding Wep Application is Stopped or Disabled or Paused.
Check the following two Fix/Solutions to resolve this issue.
Steps to fix HTTP Error 503. The service is unavailable: Solution 11. Open the Internet Information Services (IIS) by running the command inetmgr
2. Expand the Root node, expand Sites, and right-click on your Application, click Manage Web Site ->Advanced Settings
3. Note down the Application Pool name under General settings and close the window
4. Now go to Application Pools section, here you can see the corresponding Application Pool is in Stopped state. right-click on the Application Pool and Start it, also restart your Web Application.
5. Now your problem would be solved, if not solved then check the below solution.
Fix HTTP Error 503. The service is unavailable: Solution 2Issue may be solved for some of them after completed the above steps. But in my case, I have started Application Pool, then I restarted my Web Application. Then when I connect my webpage, once again I got the same problem, then I went to further analyze from the event log. I found three System Events, Event ID 5021, Event 5057, Event 5059.
Event ID 5012 Source:
Source: Microsoft-Windows-WAS Event ID: 5021 Level: Warning Description: The identity of application pool AuditAppPoolV4 is invalid. The user name or password that is specified for the identity may be incorrect, or the user may not have batch logon rights. If the identity is not corrected, the application pool will be disabled when the application pool receives its first request. If batch logon rights are causing the problem, the identity in the IIS configuration store must be changed after rights have been granted before Windows Process Activation Service (WAS) can retry the logon. If the identity remains invalid after the first request for the application pool is processed, the application pool will be disabled. The data field contains the error number.Event 5017 Source:
Source: Microsoft-Windows-WAS Event ID: 5057 Level: Warning Description: Application pool AuditAppPoolV4 has been disabled. Windows Process Activation Service (WAS) did not create a worker process to serve the application pool because the application pool identity is invalid.Event 5019 Source:
Source: Microsoft-Windows-WAS Event ID: 5059 Level: Error Description: Application pool AuditAppPoolV4 has been disabled. Windows Process Activation Service (WAS) encountered a failure when it started a worker process to serve the application pool.From the above Event IDs, it clearly indicates the root cause of the problem is Identity of the Application Pool. The given user Identity may be invalid due to expired password or locked or some other reason. So now we need to change it to new user Identity
1. Go to the Application Pools section, right-click on the Application Pool, click Advanced Settings.
2. You can see the Identity name under Process model section in the opened window. click Identity name to Edit.
3. Click the Set button, enter new user credentials, and click OK.
4. Now Restart the Application Pool and Restart your Web Application.