We have been working on the back end code quite a bit working on optimizations and ensuring solid maintainable code. As a result deletion URL's have changed slightly. Instead of looking like this:
https://imgchest.com/p/delete/post_string
We have changed to the following to maintain consistency with the rest of our post routes:
https://imgchest.com/p/post_string/delete
Please adjust accordingly, and we apologize for any inconvenience.