How to fix the “Server error in '/' application” error

There are various reasons for why you may encounter a “Server error in '/' application”. Often the error message provides a bit more detail of what’s wrong. In most cases, the server-side error message is related to IIS (Internet Information Services) or ASP.NET.

Contents

Requirements
Restart IIS
Update the URL
Add the MIME type
Verify the .NET Version

Requirements

Cloud Server running Windows Server 2012
ASP.NET installed

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Restart IIS

The “Server error in '/' application” can happen if IIS needs to be restarted. You can restart IIS from the IIS Manager. From your Remote Desktop connection, click the “Start” button in the lower left-hand corner and select “Administrative Tools”.

Click “Internet Information Services (IIS) Manager” to launch the IIS manager.

Administrative Tools: Internet Information Services (IIS) Manager — Start the IIS manager by clicking on it.

Select the affected server from the left-hand panel.

IIS manager: server selection — Select the affected server in the left tab.

On the right of the IIS Manager, click “Restart” to restart IIS.

IIS manager: Restart — Click on the “Restart” button to restart IIS.

Update the URL

Under some circumstances, a 404 error may be displayed as “Server error in '/' application”. When this is the case, the error description in the browser will clarify that the error has occurred because the file is missing or has been renamed.

http 404 error message — The “Server error in '/' application” can occur as an http 404 error.

To fix this problem, correct the URL in the link that triggers this error.

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Add the MIME type

If you are accessing a file with a file extension that does not have permissions to be run on the server, you will see the “Server error in '/' application” along with the explanation that “This type of page is not served”.

Message “This type of page is not served” — The “Server error in '/' application” can occur when a file extension does not have permission to run on the server.

When exploring a solution to a “Server error in '/' application”, first ensure that you are using the correct file name. The “Server error in '/' application” can occur if there is a typo in the file extension, for example a file or URL that references test.htl instead of test.html.

If the file name is correct, then you may need to add the MIME type to the server. MIME stands for Multipurpose Internet Mail Extensions. The MIME type is used to indicate what type of document it is. In the example, we are trying to run a file called HelloWorld.cshtml. The file extension .cshtml is not associated with any MIME type by default on Windows 2012.

You can add the MIME type in the IIS Manager. To open the IIS Manager, from your Remote Desktop connection, click the Start button in the lower left-hand corner and “Administrative Tools”.

Click “Internet Information Services (IIS) Manager” to launch the IIS manager.

Administrative Tools: launch IIS manager — Launch the IIS manager from the Administrative Tools section.

Click the server in the left-hand panel.

IIS manager: select server — You can select the affected server from the left tab in the IIS Manager.

Now click “Sites”.

IIS manager: “Sites” — In the left tab you can access the “Sites” folder.

Then click on your domain. In the central panel, double-click “MIME Types”.

IIS manager: symbol “MIME Types” — Adjust the MIME types individually.

Under the “Actions” column on the right, click “Add”.

IIS manager: add MIME types — Click “Add” to add a MIME type.

In the pop-up window which appears, fill in the “File name extension” and “MIME Type” fields, then click “OK”.

IIS manager: add MIME type window — To add a MIME type, you must specify the file extension and the corresponding MIME type.

Note

You may need to do an Internet search to find the correct MIME Type for your file extension.

Verify the .NET Version

Some programs, features, and file types will only run under certain versions of .NET.

You can also check your .NET version from the IIS Manager. To open the IIS Manager from your Remote Desktop connection, click the “Start” button in the lower left-hand corner and then select “Administrative Tools”.