Add Decal Component not working?

Hello there!
I am new to ue4, and i have been trying to add decals in a construction script unsuccessfully.
I tried to spawn decals from the event graph and succeeded, but I cant get it working from the add decal component function in the construction script.
I was wondering if I am doing something wrong or…?
Here is a screenshot of my blueprint!
Thank’s in advance!

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