It's hard to say without knowing anything at all about your composition. Most likely cause is running out of memory. When ever I have long, potentially problem filled renders in the cue I'll set the Secret Preferences to purge every frame and if I'm really nervous about the outcome I'll render an image sequence and turn that into a deliverable later using the AME. It safer.
To expose the Secret preferences hold down the Shift key as you click your After Effects Preferences>General option and browse to the last tab.