The plugin hasn't been updated in a year so I thought I'd update it. It now supports versions 1.8.8 to 1.17.1 and works with Paper.
I also fixed a major issue whereby if the plugin surpassed the Reddit API's rate limit for requests (60 requests in a minute), commands would be blocked.

Now player's commands run on separate threads, not blocking the main thread. If the server will have more than 60 reddit authentication requests per minute, it's not recommended to use the plugin as the commands slow down when approaching the rate limit (but not blocking the main thread).