Did you replace this constant with your own unique token?
For the following line:
updater = Updater(BOT_TOKEN, use_context=True)
you can just enter it as:
updater = Updater(BOT_TOKEN)
since the default value is not being changed to a new value.
Apparently this is a popular project. Have you attempted following the link provided here
(from a thread from a few days ago):