Network error: 26

JeorgeH

An error occurred while establishing a connection to SQL Server, connected to the network or to a specific instance: Server not found or unavailable. Ensure that the instance name is correct and that remote connections are allowed on SQL Server. (provider: SQL Network Interfaces, error: 26 - Error when the specified server or instance was detected)

claytonmoss

The reason that we get this error message is the client stack could not receive SSRP response UDP packet from SQL Browser. It's easy to isolate the issue. Here are the steps:
1) Make sure your server name is correct, e.g., no typo on the name. 
2) Make sure your instance name is correct and there is actually such an instance on your target machine. [Update: Some application converts \ to . If you are not sure about your application, please try both ServerInstance and Server\Instance in your connection string]
3) Make sure the server machine is reachable, e.g, DNS can be resolve correctly, you are able to ping the server (not always true). 
4) Make sure SQL Browser service is running on the server.
5) For any issues take a look here: SQL Server Repair

RichardL

Hi @JeorgeH

Thanks for your post. 

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Kind regards

Richard.