When you log in, do you check the box in the login area that says something like "Keep me logged in", "save" or something similar? If you leave it unchecked when you log in, it can cause the problem you describe.
TV: 2009 GMC Sierra 2500HD | Crew Cab | Std. Box | 4WD | Duramax/Allison
RV: 2000 Jayco Eagle 266 | FBS | TT
PREVIOUS: 1986 Coleman Laramie pop-up -- Still in the family!!!