Can't play commands on Heroku

[mobilegaming08]

When I tried to use it after looking at the directions carefully, it gave me an error saying something about this:

discord.ext.commands.errors.CommandInvokeError: Command raised an exception: DownloadError: ERROR: Unable to download webpage: <urlopen error [Errno -5] No address associated with hostname> (caused by URLError(gaierror(-5, 'No address associated with hostname'),))

Is there anyway I can be able fix this? Thanks in advance

(My forked repo is left unchanged btw.)