Your receiver isn't finding signals from a WAAS satellite
From many parts of North America, satellites that transmit WAAS appear relatively low in the sky (because they're in geostationary orbit above the equator). In locations that are further north, WAAS signals are more likely to be blocked by buildings, hills or other things that obstruct views toward the southern half of the sky.
Your receiver hasn't had a chance to receive useful data
WAAS data is transmitted in a cycle that repeats every few minutes. You need to be receiving signal at the right time to gather data that's applicable to your area.
Your receiver may be ignoring WASS
This really depends on your particular model. Many receivers have settings that enable/disable WAAS.