The server application is unavailable.

This problem was discovered after work today. The reference content server application is unavailable.
The Web application you are attempting to access on this Web server is currently unavailable. Please click "refresh" in the Web browser to try your request again.

Administrator Note: you can find the error details for the specific request failure cause in the system event log of the Web server. Check this log item to find out the cause of this error.

I checked it online.
Http://www.cnblogs.com/cowbird/archive/2005/02/16/104546.html
Reference content

The Microsoft Framework1.1 SP1 Security Update Program (kb886903133) can be customized to guide the webapplication program; the server application cannot be used; and The “aspnet_wp.exe cannot be accidentally stopped"

Cowbird
2005.02.15

Very angry, suddenly found that IIS applications can not browse the page, try any aspx page can not open. A new web application was created with vs.net again.

Computer environment:
Win2003, vs. net2003

Symptom:
1) when you want to browse a page, the "server application unavailable" Web application you are trying to access on this Web server is currently unavailable. Please click "refresh" in the Web browser to try your request again. Administrator Note: you can find the error details for the specific request failure cause in the system event log of the Web server.
Check the log and find that the restart aspnet_wp.exe (PID: 356) stops unexpectedly ."
2) If debugging is selected, the display is as follows:

Try:
When I thought about it, the problem suddenly occurred, and there was no software installed or virus. It was strange.
If the result found on google based on "ExecutionEngineException" is "no medicine to save", make the "worst plan" and reinstall it !. :)
Zookeeper aspnet_wp.exe (PID: 356) unexpectedly stopped "was checked on google and found that the solution on the internet is nothing more than re-installing IIS, re-installing the system, re-installing the framework or vs.net.
In this case, select the simplest IIS reinstallation and find that the problem persists.
Next, choose to fix and install win2003. After installation, the problem is fixed.
We all know that the patches will disappear after the installed operating system is repaired. I updated all the patches one by one and then ran the updates again.

Cause:
Obviously, the cause of the problem is the patch. Keep trying and locate the Microsoft. NET Framework Version 1.1 Service Pack 1 Security Update Program (KB886903) to delete it and solve the problem. Depressed! It took me a whole day to demand "compensation" from Microsoft ". I checked on the Internet and found that foreigners have encountered the same problem: http://www.mcse.ms/message1412685.html.

The patch is being installed when the server is automatically updated today. I don't care about any patches. I just put them aside. I thought it would be very troublesome to re-install the patch. I simply quit.

It seems that this problem may be caused by no patching?

So I fixed the patch and restarted the computer, and the problem remained.

This occurs only when the virtual directory of ASP. NET 1.0 is restarted.
The virtual directory of ASP. NET2.0 is normal.

After the restart, an ASP. NET2.0 directory appears. The virtual directory of ASP. NET 1.0 is normal.

Later, I checked the system logs and found the real cause. It is impossible to run two different ASP. NET versions in the same IIS process. Use the IIS administration tool to reconfigure the server to run applications in a separate process.

Change the application pool of the next virtual directory. Use different application pools for the virtual directories of ASP. NET 1.0 and ASP. NET 2.0.
Done! Continue to work!