Inability to connect to server may be a problem with discontinued 3G cellular service from AT&T. From Reddit: Early Airsense machines had only 3G. Machines made in the last 2 years have 4g. If you are unsure, you need to access the clinical settings and look in the ABOUT section in settings. It will say 4g if you have 4G. To access clinical settings on an Airsense, press the large round button while simultaneously pressing the house button for about 5 seconds. Select settings and scroll down