Please check if turning 'Passive mode' (Deployment/Advanced options) on makes any difference. If it doesn't, please try the following:
shut down WebStorm
delete the idea.log
enable debug logging for 'com.jetbrains.plugins.webDeployment' category (see devnet.jetbrains.com/docs/DOC-1202 for details)
recreate your problem and send the idea.log to Jetbrains support