MyLittleAdmin on Plesk server does not show databases list: URL that was requested does not exist

Symptoms

1. MyLittleAdmin does not show databases list:

   CONFIG_TEXT: URL that was requested does not exist.
   The page isn't redirecting properly.

   OR

   CONFIG_TEXT: Timeout expired.
   The timeout period elapsed prior to completion of the operation or the server is not responding.

2. An attempt to get the User Databases menu stuck at:

   CONFIG_TEXT: Retrieving data...

3. Cannot open the User Databases menu on new browser tab:

   CONFIG_TEXT: Server error
   404 - File or directory not found.
   The resource you are looking for might have been removed, had its name changed, or is temporarily unavailable.

Cause

The cause is on MyLittleAdmin side: it fails to handle database connections when there are a lot of databases.

Resolution

Get more detailed error message using the steps below and contact MyLittleAdmin support for assistance:

1. Connect to the server via RDP.

2. Enable debug mode in the %plesk_dir%MyLittleAdmin\config.xml:

   CONFIG_TEXT: <debug value="true"/>

3. Change the httpRuntime maxRequestLength value in%plesk_dir%MyLittleAdmin\web.config:

   CONFIG_TEXT: <httpRuntime maxRequestLength="204800" maxQueryStringLength="2097151" />

4. Comment out the httpErrors block in%plesk_dir%MyLittleAdmin\web.config:

   CONFIG_TEXT: <!--
   <httpErrors errorMode="DetailedLocalOnly" defaultPath="./error/404.html" defaultResponseMode="ExecuteURL">
   <remove statusCode="404" subStatusCode="-1" />
   <error statusCode="404" prefixLanguageFilePath="" path="./error/404.html" responseMode="ExecuteURL" />
   </httpErrors>
   -->

5. Right-click the User Databases menu in myLittleAdmin and press the Open in New Tab button to get the detailed error output:

   • The output of the error may be listed on the page in plain text (the output may be formatted differently, so use URL decoder to get human-readable text):

     CONFIG_TEXT: HTTP Error 404.15 - Not Found
     The request filtering module is configured to deny a request where the query string is too long.
     Detailed Error Information:
     Module RequestFilteringModule
     Notification BeginRequest
     Handler PageHandlerFactory-Integrated-4.0
     Error Code 0x00000000
     Source: .Net SqlClient Data Provider
     Message: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
     Stack trace: at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
     at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
     at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)

     OR

     CONFIG_TEXT: Offending URL: .Net SqlClient Data Provider<br /><br /><strong>Message:</strong> Execution Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding.<br /><br /><strong>Stack trace:</strong> at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)

   • If there is a simple 404 error:

     CONFIG_TEXT: 404 - File or directory not found.

     then copy the URL of that page and decode it using URL decoder. It will display similar content regarding .Net SqlClient Data Provider.