Here's the recommended procedure for connecting to a CO/CT lock:
1. Connect cable to tablet.
2. If app isn't open, open it now. (it's ok to have the app already open before step 1, just make sure it's not in the door operations actions yet.)
3. Plug the box side of cable into the bottom of the door.
4. Press the Schlage button on the lock twice. It should flash Green - Red once.
5. After the Green-Red, you can go into Connect to CO/CT locks and it should find the lock. The first time it may take a bit longer than usual, but you should see the Schlage button show Red blinks and you'll know it's trying to attach.
6. If it's not working, hit the back button and wait about 5-10 seconds, then go back into the Connect to CO/CT button and press the Schlage button twice.
7. If it's still not working, try restarting the StratIS application or rebooting the tablet.
If you're having trouble getting the Green-Red flash when hitting Schlage button twice, you might try pulling the Green rubber casing off the black case to give the USB plug a bit more room to go into the lock's usb port.