在Django中链接Urls

I recently started learning as a way of setting foot in python programming. I've been facing problems with URLs since I'm a beginner. So I've been doing this signature verification web app. I'm not facing major problems except when it comes to URL patterns. When I enter the localhost address and the port and execute the program, it displays this error displayed here. I've gone to the URL files on Django and I see no errors on the code that I've written and also on the main folders URL. Can someone help me find the problem or what I'm doing wrong by checking the images and telling me? Thank you to all the people who checked this out.