Time Machine doesn't open

Hi,

I want to delete all my files and documents on my MacBook Air. So I made a Time Machine backup. Then I wanted to check in the Time Machine App if the backup is alright. But somehow Time Machine wont open.

I went to Finder, typed in the search "Time Machine" clicked on the app and pressed Control+O (this causes a app to open). It didn't work. In my Doc on the bottom of the screen was the Time Machine App as well. All other apps open normally, but Time Machine shows no reaction.

I use Time Machine every week, so this is very unusual for me.

My mac is: MacBook Air, mid 2013, 13-inch, I use macOS Sierra, version 10.12.4.

I hope someone will have an answer..

Thanks