Response Code 401 when spraying Okta with valid credentials

[tkraus13]

When using the Okta module, Trevorspray returns a Response code 401 for every attempt, including for a correct set of credentials. The command being used is:
trevorspray -u test_emails.txt -m okta -p 'password' --delay 60 --jitter 10 --lockout-delay 30 -n --ssh ubuntu@ip_address --key ~/id
I know which username the password is valid for and have tested it by successfully logging in at "domain.okta.com," and have double checked that the username is included in the file test_emails.txt. I may be missing something in the command, but as far as I can tell from the github README my command is correct.