If you like to keep multiple tabs open on your browser, you may find that the tab with your member dashboard reverts to a login screen that looks similar to this:
This happens because each dashboard has a 1-hour expiration due to inactivity.
You've probably also discovered that your credentials do not work on this screen. In order to get back to the dashboard you were viewing, go back to your MLS or Association login (wherever you typically access the dashboards from).