I have been using remote interpreter all the times before, but suddenly it shows failed error message: can't run python interpreter: error connecting to remote host: 
I am using SFTP, and I have tried "Test SFTP connection", got success message with the same host.
I am wondering how do I see verbose message in the remote debugging connection. 
I am using PyCharm 2017.2 professional.
Solve the problem. There are two places to edit the same remote interpreter. One is from Default Setting-> Project Interpreter -> Setting Icon -> More -> edit icon, another is from Tools -> Deployment -> Configuration. The settings in both places need to be correct for the same remote interpreter.
For some reason, the password in my first location was cleared.
Pycharm stopped working in remote interpreter