We implemented a fix and are currently monitoring the result.
This issue was caused by a big influx for our size of new guilds using Earthling for levelling. Our levelling code and API couldn't handle the amount of requests being made to update and check for details in our database. During the past few days, this has resulted in Earthling going online and offline constantly - up to 50 times a day. Secondly, it resulted in the bot failing to respond to application slash command requests, which we understand is frustrating. We have optimised our code to ensure that the growth of Earthling should be a smooth ride from here, along with the bot working as usual from now.