There are multiple reasons why you may not have received an Exposure Notification. Either you or the person who tested positive might not have had Bluetooth enabled or had Exposure Notifications turned on. The person who tested positive may not have chosen to share their diagnosis in the app to notify others. You might not have been close enough to them for a long enough period of time to receive a High Exposure or Low Exposure Notification. In addition, it is possible that either of your Bluetooth signals was obstructed. Click here for more information about Bluetooth signals.