As of today, one sash of the patio door no longer opens, which is the sash with the handle.
The handle is in the up position, so it is more or less tilted, but the sash is leaning against the wall, so it cannot be tilted. Opening the handle to the left in the horizontal position is also no longer possible. At the top in the left corner, the sash rests against the frame and can be pushed back a bit, so no closing occurred...
Now I am at a loss, I don't want to use force, I'm afraid of breaking it.
It looks like the door was opened in a tilted position. Sometimes it helps to close, press in the corner and play with the handle. Then all the way to closing.
Perhaps because of the hot weather, the door had warped a bit.