Above: Login using MyAccount @ Marriott.com; Right-Click Marriott Rewards Insiders. Depending upon your browser, Select 'Open Link in New Window' or 'Open Link in New Tab'.
To illustrate Pingreeman's solution, Login using the My Account module located in the upper right hand corner of the home page at Marriott.com
When Marriott.com authenticates you, your account name, membership level and number of points is displayed.
Right-click Marriott Rewards Insiders and select the option supported by your browser to open the link in a new window or a new tab.
If you encounter a session timeout, go to the window with Marriott.com and login. After the refresh, return to the Insiders window and resume activity.
Typically, system servers are supposed to be 99.9999% operational. On rare occasion, the Marriott Rewards Insiders server and/or the Marriott.com authentication server or both will wipeout. Again, these breaches in service are rare but they can happen at the most inconvenient times as scrabble observes.
This is a problem that I wrote about a while ago as well. When the system times out and you go to do something you do not know you have timed out until after you have started somethings else. It makes you log back in and start all over. I have put in a request to at least bring you back to where you were like it does if you have not logged in and book a reservation then log in once at the confirmation site. It just continues. All pages should act the same way. It is a pain.