Create unable-to-establish-a-connection-to-the-database-when-the application-is-deployed.md

Author: silviyaboteva

knowledge-base/unable-to-establish-a-connection-to-the-database-when-the application-is-deployed.md

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+---
+title: Error Unable to establish a connection to the database when the application is deployed
+description: Upon deploying an error message Unable to establish a connection to the database when the application is deployed has been thrown
+type: troubleshooting
+page_title: Error Unable to establish a connection to the database when the application is deployed
+slug: unable-to-establish-a-connection-to-the-database-when-the application-is-deployed
+position: 
+tags: Configuration
+ticketid: 1361723
+res_type: kb
+---
+
+## Environment
+<table>
+	<tr>
+		<td>Product Version</td>
+		<td>12.2.18.912</td>
+	</tr>
+	<tr>
+		<td>Product</td>
+		<td>Progress® Telerik® Reporting</td>
+	</tr>
+</table>
+
+
+## Error Message
+The error message 
+```
+Unable to establish a connection to the database. Please verify that your connection string is valid. In case you use a named connection string from
+the application configuration file, make sure the name is correct and the connection string settings are present in the configuration file of your
+application.
+------------- InnerException -------------
+The 'DbProviderFactories' section can only appear once per config file.
+```
+ is returned from the attempt to deploy an application to a server.
+
+## Cause\Possible Cause(s)
+The issues is caused by multiple **DbProviderFactory** entries in the *machine.config* file on the server. 
+
+## Solution
+Check the specified configuration files and compare them with development machine's ones. Alternatively, some troubleshooting instructions are discussed in the following stackoverflow threads:
+- [Override machine.config by web.config](https://stackoverflow.com/questions/2201242/override-machine-config-by-web-config)
+- ['DbProviderFactories' section can only appear once per config file error](https://forums.asp.net/t/1693277.aspx?+DbProviderFactories+section+can+only+appear+once+per+config+file+error)