I'll go through both procedures, since both the deletion of a user by a user doesn't work, nor the deletion of a user by a superuser.
As a User, i start from the dashboard, already logged in.
I go to my Account setting and scroll down and click the "Delete my Account"-Button.
A popup opens, with information and an input box that requires my password aswell as two buttons, "Yes, Delete" and "Cancel".
I enter my password, click the "Yes, Delete"-Button and on top of the Popup an Error message appears "Unable to delete Account". When i check the network-tab in the dev console, i see that i received a 500-error.
As a superuser, i log into the LMS Administration, and under "AUTHENTICATION AND AUTHORIZATION" i enter the "Users" menu.
There i check the box of the user i wish to delete, and in the actions dropdown i select "Delete selected users" and click "Go"
A new page loads, that ask me if i'm sure, a summary of what is getting deleted and two buttons, one of them labeled "Yes, i'm sure".
I click said button, and the page loads to the LMS-layout, where it says that there has been a 500 Server Error.