Shimano Sora rear derailleur install, U-ring on bolt
That black strip to which your derailleur is attached, which can be assumed to be the hanger, looks strangely narrow, like a metallic popsicle stick. Is that by chance a part related to the Shimano Direct Mount (TM) system? Some sort of adapter link plate? It seems incompatibly narrow for the derailleur: it's fitting entirely into the semi-circular gap in the derailleur's bolt plate (what we're calling "the opening" in this Q&amp;A.) That shouldn't be happening; the hanger shouldn't be pressing against the axle retainer clip at all.

Assuming there is no other compatibility issue, and you want to keep that hanger, one way to fix this would be to put a suitably dimensioned stainless steel washer between it  and the derailleur, to effectively make the hanger look as if it has a larger area around its receptacle for the derailleur to mate with.

The real fix is to install a traditional standard mount hanger that is compatible with the Sora.

For reference, here is a picture of how my Sora is attached to a standard type hanger. Notice also how the hanger is angled; it doesn't protrude rearward, but slants forward, so it doesn't anywhere near align with that opening recess in the derailleur's end plate.