If you are having difficult with clicking...
Click/highlight the mask thumbnail in the Layers Panel
Open the Channels Panel (Window > Channels)
Turn on visibility for the mask channel
The Option/Alt-click or Option/Alt-Shift-click on the mask thumbnail are merely shortcuts for these steps. If you open the Channels Panel, then use the shortcuts ...
Looks like you are merely clipping a visible line to the shape below - that's not going to work for what you are trying to do.
If I've read your question correctly, sounds like you want create an actual vector mask. Basically, you'd use the Pen Tool to make a Path (in the tool options set "path" instead of "shape"), then do Layer > ...
One object should not act as both a visible object and a clipping mask.
Clipping masks should be separate objects.
Undo your mask
Copy the parent shape - Edit > Copy
Paste in Front - Edit > Paste in Front
Hold Shift and select the shape you want to mask
Now create the clipping mask.
You must need a vector shape/ object to create mask in XD.
In first example rectangle is what masking the fruit image.
But In second case there is no shape to mask the cat.
A picture itself is not a mask! You have to have a vector shape/ object to mask an image, otherwise it simply won’t happen.
And If you think you will include/incorporate an image into ...