UnicodeError 'idna' encoding when working with Heroku, Redis and Flask

I have a Flask REST API hosted on Heroku with a Heroku-Redis server.

When code that tries to access the Redis server is executed I get the following error.

UnicodeError: encoding with 'idna' codec failed (UnicodeError: label empty or too long)

The code that seems to cause this error is,

revoked_store.set(access_jti, 'false', ACCESS_EXPIRES * 1.2)
revoked_store.set(refresh_jti, 'false', REFRESH_EXPIRES * 1.2)

The connection is set here:

revoked_store = redis.StrictRedis(host=os.environ.get('REDIS_URL'), port=6379, db=0, decode_responses=True)

From looking at various other posts I think this error is caused by the Redis URL being too long (>64 characters). See here.

I am not sure how to fix this effort so any help would be appreciated.

If you require more information, please let me know.

Thank you.