If you are a long-time GBDX customer, you may have a username that is not an email address. The new authentication system does not accept usernames in any format other than an email address.
In the Postman client, check your environment variables. The key "username" should have a "value" that is the email address associated with your account.
In gbdxtools, check your config file to make sure the value for user_name is an email address.
A. Use your GBDX credentials to sign into https://gbdx.geobigdata.io.
Sign into the web application at https://gbdx.geobigdata.io. If you haven't signed the latest TOS, it will prompt you to read and accept them now. If you still get a 401 error, you can contact firstname.lastname@example.org for help.
If you're a new user, make sure you've validated your email address. You should have received a welcome email telling you how to do that. If it's been awhile, your invitation may have expired. In that case, contact email@example.com for assistance.
However, older versions will still work if you clear the token from your gbdxtools config file. See Instructions for gbdxtools Users for more information.
If your workflows use "user impersonation", they most likely failed due to tokens being expired during the deployment. These workflows will need to be resubmitted.