Fer security reasons, Simul sessions only last while Word is open. When you close Word you will need to start a new editing session by selecting the 'Open in Word' button on the Simul website (www.simuldocs.com).
This means that you cannot open documents from Words recently opened files list and doing so will result in the following error:
On Mac OSX, particular versions of Office can show the above session expired message when opening directly from the Simul website. This is caused by an issue with Microsoft Word but can usually be resolved by the following:
* This fix requires that you have a Microsoft account.
Signing out and in again with your Microsoft account resets the protocol which Simul relies on to safely transfer your documents to our servers.