Status : Failure -Cannot connect to Microsoft SQL Server on localhost when connect Oracle Sql Developer

 

I had this problem and I fixed it by enabling the TCP/IP protocol for the server instance. You can do that by

1. Open SQL Server Configuration Manager
2. Expand SQL Server Network Configuration
3. Select Protocols for MSSQLSERVER
4. Enable TCP/IP

After this, You need to restart the SQL Server service to make it effective.