Depending on your needs, there are two lines of support for iThenticate.
iThenticate Training & Help Desk
Issues With First-Time Access Request & Logging In
If you are having issues requesting and/or accessing your iThenticate for the first time, or you cannot reset your password, submit a Help.UNM ticket requesting your account authorization e-mail be resent to the e-mail on file for your account. (Note: This action will reset your password for you.)