Teleport Problems

I'm using Teleport with a modicum of success, but two things are frustrating. For unknown reasons, it sometimes just won't work after it has been working just fine. Or vice versa, i.e., I try and try and it won't go over to the other iMac; than once I have stopped trying, it will pop over there unexpectedly. I check all settings and nothing seems amiss. It also seems to require clicking open after one or the other computer restarts or sometimes just after waking the computer up. I have it set to automatically recognize the computers, but it is very troublesome for it to just quit for no reason. Any help to prevent it or to fix it when it happens would be much appreciated.

I am using it with Sierra on two iMacs, one i5 and the other i7--if that makes any difference. They are brand new.