Manage passwords
When your org includes the use of one or more AD instances, it's important that you ensure passwords are managed properly. Specifically, a user's AD password and Okta password must always match.
Synchronize passwords provides an overview of how to keep user passwords in sync, either from Okta to AD, or from AD to Okta.
You can migrate user passwords from AD to Okta and then have Okta handle user authentication, which eliminates the need to use delegated authentication. See Password migration from AD to Okta.