Working with Professional edition of PyCharm, I'm trying to configure a server for remote deployment of my project over SFTP with OpenSSH + authentication agent as auth type. I have tried to configure PyCharm in Settings > Build, Execution and Deployment > Add server. However, even though I setup and verify successful configuration by Test SFTP connection button, as soon as I click Apply or OK, the User name becomes blank for some reason. Thereafter, when I try to sync with the remote server, the connection fails.
I've found a possible workaround by changing Host name to user@host form instead, which works, but then I can't use the same server configuration when I try to setup a remote interpreter under Project > Project Interpreter > Add SSH interpreter. (there it shows my host url as ssh://null@host). I'm guessing the null is there because PyCharm is somehow not saving the username. I've tried to edit the .idea/webServers.xml file, but couldn't find appropriate key-value pair to change there for user name to be preserved.
What worked for me was first going to the following tab:
Preferences -> Build, Execution, Deployment -> Deployment [Connection Tab]
and then inserting my  in the "User name" blank.
Note: your user name appears in the ip address of you ec2. e.g. username@@xxx.amazonaws.com
PyCharm remote deployment: user name not being saved