Azure Studio connection Error with MS SQL on Linux Mint 19.2

I have MS SQL 2017 running on Linux Mint 19.2. I used "sqlcmd" to verify that it's running, and the reported version is "Microsoft SQL Server 2017 (RTM-CU16) (KB4508218) - 14.0.3223.3 (X64)" However, when I tried connecting to the database server using Azure Studio version 1.10.0 (For Linux) it failed with error as followed: "System.Data.SqlClient.SqlException (0x80131904): 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. (provider: TCP Provider, error: 40 - Could not open a connection to SQL Server)"

All things are running on a local machine. My system is " 4.15.0-54-generic #58-Ubuntu".

At some earlier point in time, the studio was able to connect to the database server. Then during a week long period, I keep installing new softwares to my machine, and this suddenly happened. This could be the results of some new software updates. However, I could not pin down what software updates / installation caused it. It's worth to repeat that the database server is truly running, on default port 1433, since I can execute a lot of sql script using sqlcmd tool.