How to resolve “Network-related or instance-specific error" while establishing a connection to a SQL Server on a remote computer on the home network.
I have two laptops (both running Windows 10, 64-bit) that are connected to my home network using wifi. Here are details about each laptop: Laptop #1: 
By default named instances are bound with dynamic ports and the SQL Browser service is the one that redirects the client connections to named instances. For this to happen you need to ensure the following: Ensure SQL Browser service is running Create a rule in windows firewall (where SQL Service and SQL Browser services are installed) to accept in-bond communication on port numbers UDP: 1434 and TCP:1433 You could also make connections without relying on SQL browser service. For that, you must configure the custom port and use port number in connection string instead of instance name (example: 10.0.0.5,1435)
Once you get this message (['any' 1433]) in the SQL Error log, the SQL server is ready to accept connections, but in your case, there is something else blocking your connections. Most probably it's a firewall, Create a rule (as mentioned above), do telnet again, if it works, you should be able to make the connection. If you are unable after firewall entry, make sure there is no network-level blocking happening on those specific port numbers.I enabled Telnet Client on Laptop #2's PowerShell but could not connect to the host 10.0.0.5:1433. Until telnet succeeded the connections could not be established. Why is there a network-related or instance-specific error occurred while establishing a connection to sql server? Your connection string was probably overridden when you copied your new website version on the server. Please check the connection string on the web. config and see if it is valid.