Well, odds are you haven’t enabled CORS for our domain in your app’s server. Please follow these instructions.
In general such errors occur in case your network is unstable and the web socket between your browser and our server is disconnecting. Please check your network settings and verify whether other team members experience the issue.
It means that you haven’t given permission to the browser to copy and paste text and images to the clipboard. Just click on the icon next to the URL to enable it.
In case you are using Chrome, you may also go to Settings - look for "Clipboard' and allow Loadmill to use it.