To fix the issue, allow MS SQL Server ports in Firewall settings

Symptoms

1. You start Acronis SharePoint Explorer Console and attempt to connect to the Agent machine;
2. The connection attempt fails with the following error messages:

   Failed to initialize local farm
   A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections.

Cause

Firewall on the Agent machine prohibits the Agent to connect to the MS SQL server and initialize the connection with Console.

Solution

Allow MS SQL Server ports in the Firewall settings.

By default MS SQL is using TCP ports 1433, 1434 and UDP port 1434. Although in some cases, it may be set to use a dynamic port. In such cases, the port number will be randomly generated every time MS SQL server restarts. It is recommended to change ports that the MS SQL Server uses to default TCP 1433 and allow it in the Firewall.

To change the SQL server port, do the following:

1. Run SQL Configuration Manager;
2. Go to SQL Service Network Configuration;
3. Select your SQL instance and go to Properties of TCP/IP protocol;
4. On the IP Addresses tab, change the TCP port of all IP addresses to 1433.

More information

See also MSDN: Configure the Windows Firewall to Allow SQL Server Access.