Why can't I create any Reports on DMs sent to me?

Whenever I try to report a message in my DMs it says "Couldn't Create Report" this is extremely annoying and also probably problematic because people need to be able to report abusive or rule breaking DMs and if it gives them an error it's likely that people in that position will not report them and instead simply block the person.

Can we maybe get this problem fixed, or if it's intentional can we get an explanation why it was done?