@Putteringalong 

The smart plug is essentially a vampire tap,  What vampire taps are plugs that cut all power to a connected device.  What could be happening and I am no expert in Garage doors is that the sensor need constant power to remain active.  and it needs a "reset" to restore function.  The best thing i can think of is contact the door opener manufacture and explain what is happeing they should be able to give you better insight. 

@Carl 

Well I have egg all over my face. I had reached out to the opener manufacturer; they said I just need to wait awhile. I had waited for several hours.

What I had NOT done was test power down/up in the naked wall socket. I have experienced a rare power outage in the past four years, but not had any issues with the opener. Thinking back doubt if any of the outages happened with the garage door open. I discovered the problem with to door open when I installed the smart plug.

So I just got ladder out, took the smart plug out and plugged the opener directly in the outlet - the sensor lights flashed until I blocked the light path between them and then connected with the sensor lights on steadily.

Thanks for your reply Carl and I'm sorry for the wild goose chase!

@Putteringalong 

No worries if anything thats is what we are here for to help bounce ideas and find solutions.  Glad to have helped 

The door was behavinf where strage. As I/m not specialist, I did not know what to do in this case. One of my neighbors found adviced a solution. Here in Calgary we have a great team of profisional that realy help me with my garage door. I called Advantage Garage Doors and received the quickest service I has ever seen. The guys have come very quick found a probles and repaired the door. It is very hard to find a professional team in such a small town. But I have managed to do this

@AmyYoung 

The "problem" is with the safety sensors at the bottom of the vertical rails of the track the garage door travels on. I think you will see that after power cycling the opener that the lights blink - they need to on solid. All you have to do to stop blinking and shine steadily is break the light path. The most common way to to this is back the car out of the garage - the wheels do the trick. You can also wave your foot in the light path and they will connect.