Can only edit entries created by the user in Microsoft Lists + Network error when using Patch functi

Hello,

I have the following issue: I can only edit entries in a Microsoft List that are created by the user (me in this case). Same goes for everyone else in the organization. The list setting that would make this happen has been deselected from the get go. Furthermore, when I try to edit an entry that's not made by me using the PowerApps custom form, I get the following error: Network error when using Patch function: The requested operation is invalid.

Thank you in advance