# 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**. ## Requirements - Cloud Server running Windows Server 2012 - [ASP.NET](https://www.ionos.ca/digitalguide/websites/web-development/what-is-aspnet/) installed ## 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”. [![Image: Windows panel “Administrative Tools”](https://www.ionos.ca/digitalguide/fileadmin/_processed_/e/9/csm_admin-tools_4823bff134.webp "Windows panel “Administrative Tools”")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/admin-tools.jpg) Windows panel “Administrative Tools”. Click “**Internet Information Services (IIS) Manager”** to launch the IIS manager. [![Image: Administrative Tools: Internet Information Services (IIS) Manager](https://www.ionos.ca/digitalguide/fileadmin/_processed_/8/b/csm_click-to-launch-iis-manager_3141055d42.webp "Administrative Tools: Internet Information Services (IIS) Manager")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/click-to-launch-iis-manager.jpg) Start the IIS manager by clicking on it. Select the affected server from the left-hand panel. [![Image: IIS manager: server selection](https://www.ionos.ca/digitalguide/fileadmin/_processed_/1/a/csm_click-to-expand-the-server_df256fe40d.webp "IIS manager: server selection")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/click-to-expand-the-server.jpg) Select the affected server in the left tab. On the right of the IIS Manager, click “Restart” to restart IIS. [![Image: IIS manager: Restart](https://www.ionos.ca/digitalguide/fileadmin/_processed_/e/c/csm_click-to-restart-iis_1751b7e100.webp "IIS manager: Restart")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/click-to-restart-iis.jpg) Click on the “Restart” button to restart IIS. ## Update the URL Under some circumstances, a [404 error](https://www.ionos.ca/digitalguide/websites/website-creation/what-does-the-404-not-found-error-mean/ "What does the '404 Not Found' error mean?") 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. [![Image: http 404 error message](https://www.ionos.ca/digitalguide/fileadmin/_processed_/7/0/csm_404_a35e07b075.webp "http 404 error message")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/404.jpg) 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. ## 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”. [![Image: Message “This type of page is not served”](https://www.ionos.ca/digitalguide/fileadmin/_processed_/4/9/csm_type-of-page-is-not-served_be24397014.webp "Message “This type of page is not served”")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/type-of-page-is-not-served.jpg) 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](https://www.ionos.ca/digitalguide/server/know-how/file-extension-overview/ "File extension overview") *.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”. [![Image: Windows panel “Administrative Tools”](https://www.ionos.ca/digitalguide/fileadmin/_processed_/e/9/csm_admin-tools_4823bff134.webp "Windows panel “Administrative Tools”")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/admin-tools.jpg) The IIS manager can be found in the Administrative Tools section. Click “Internet Information Services (IIS) Manager” to launch the IIS manager. [![Image: Administrative Tools: launch IIS manager](https://www.ionos.ca/digitalguide/fileadmin/_processed_/8/b/csm_click-to-launch-iis-manager_3141055d42.webp "Administrative Tools: launch IIS manager")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/click-to-launch-iis-manager.jpg) Launch the IIS manager from the Administrative Tools section. Click the server in the left-hand panel. [![Image: IIS manager: select server](https://www.ionos.ca/digitalguide/fileadmin/_processed_/1/a/csm_click-to-expand-the-server_df256fe40d.webp "IIS manager: select server")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/click-to-expand-the-server.jpg) You can select the affected server from the left tab in the IIS Manager. Now click “Sites”. [![Image: IIS manager: “Sites”](https://www.ionos.ca/digitalguide/fileadmin/_processed_/b/e/csm_click-to-expand-sites_8e662c1a2a.webp "IIS manager: “Sites”")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/click-to-expand-sites.jpg) In the left tab you can access the “Sites” folder. Then click on your domain. In the central panel, double-click “**MIME Types”**. [![Image: IIS manager: symbol “MIME Types”](https://www.ionos.ca/digitalguide/fileadmin/_processed_/7/8/csm_double-click-mime-types_5c3f6d0632.webp "IIS manager: symbol “MIME Types”")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/double-click-mime-types.jpg) Adjust the MIME types individually. Under the “Actions” column on the right, click “Add”. [![Image: IIS manager: add MIME types](https://www.ionos.ca/digitalguide/fileadmin/_processed_/3/d/csm_click-to-add-a-mime-type_79d200304e.webp "IIS manager: add MIME types")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/click-to-add-a-mime-type.jpg) 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”**. [![Image: IIS manager: add MIME type window](https://www.ionos.ca/digitalguide/fileadmin/_processed_/b/c/csm_mime-type-pop-up_368c939a79.webp "IIS manager: add MIME type window")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/mime-type-pop-up.jpg) 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”. [![Image: Windows panel “Administrative Tools”](https://www.ionos.ca/digitalguide/fileadmin/_processed_/e/9/csm_admin-tools_4823bff134.webp "Windows panel “Administrative Tools”")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/admin-tools.jpg) The IIS manager can be found in the “Administrative Tools”. Click “**Internet Information Services (IIS) Manager”** to launch the IIS manager. [![Image: Administrative Tools: Internet Information Services (IIS) manager](https://www.ionos.ca/digitalguide/fileadmin/_processed_/8/b/csm_click-to-launch-iis-manager_3141055d42.webp "Administrative Tools: Internet Information Services (IIS) manager")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/click-to-launch-iis-manager.jpg) Launch the IIS manager from the Administrative tools. Click to expand the server in the left-hand window panel. [![Image: IIS manager: server selection](https://www.ionos.ca/digitalguide/fileadmin/_processed_/1/a/csm_click-to-expand-the-server_df256fe40d.webp "IIS manager: server selection")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/click-to-expand-the-server.jpg) You can select the affected server from the left side of the IIS manager. Click on “**Application Pools”**. [![Image: IIS manager: “Application Pool” among selected servers](https://www.ionos.ca/digitalguide/fileadmin/_processed_/5/3/csm_application-pools_803fe8f46b.webp "IIS manager: “Application Pool” among selected servers")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/application-pools.jpg) Select the Application Pools from the left panel of the IIS Manager. Right-click on the Domain Name and click on “**Basic Settings”.** [![Image: IIS manager, Application Pools: contextual menu, “Basic settings”](https://www.ionos.ca/digitalguide/fileadmin/_processed_/a/9/csm_basic-settings_8e72930097.webp "IIS manager, Application Pools: contextual menu, “Basic settings”")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/basic-settings.jpg) You can access the settings by right-clicking on the domain name. In the pop-up window which appears, select the .NET version from the drop-down menu, then click “**OK”** to confirm your choice. [![Image: IIS manager, Application Pools: select .NET version](https://www.ionos.ca/digitalguide/fileadmin/_processed_/d/d/csm_select-net-version_4df47e8189.webp "IIS manager, Application Pools: select .NET version")](https://www.ionos.ca/digitalguide/fileadmin/DigitalGuide/Screenshots_2020/select-net-version.jpg) Select your .NET version. This is a markdown version of: [https://www.ionos.ca/digitalguide/server/know-how/fix-server-error-in-application/](https://www.ionos.ca/digitalguide/server/know-how/fix-server-error-in-application/) for AI/LLM consumption.