You can refer to the below steps to resolve the login issue:
Follow the instructions from the email you received from the DMV, and click “SIGN IN WITH YOUR DMV ACCOUNT” from the MVProctor DMV homepage.
Please click on the ‘Login’ button, then enter your registered California DMV email address and password to login into your account.
In case, if you are looking to change or forget the login password then please click on Forgot Password.
Make sure to enter your registered California DMV email address, then click on the ‘Reset my password’ button.
A password reset email has been sent to your registered California DMV email address, please check your email.
You will see the ‘Reset Password’ button in the password reset email, please click on it.
Please set your New password, confirm your New Password & click on the ‘Save’ button.
Your password has been changed successfully!
Now please enter your username and new password & click on the ‘Sign in’ button to login into your account.