If you're using the Google or Facebook SSO (Single Sign On) method to login to your Motion Array account, you will need to create a new password in order to login to the Extension Panel or Plugins for Premiere Pro.

You can create a password here (Reset your password), then try logging into the Plugins again (see Email Login Method):

This may affect the way that you login to motionarray.com (e.g. if you're unable to login to your Motion Array account from motionarray.com by using the Facebook or Google Login after doing this, you may need to try entering your email address instead.)