This guide will walk you through resetting your password through the Portal.
Step 1: Sign in to your My Apps Portal: On the Left side column, click on My Account, from the drop-down list, pick Change Password

Step 2: The Multi-Factor Authentication will prompt you

Step 3: You will be prompted to set a new password. Keep in mind that you can not reuse any part of the older passwords

Once you have saved the password, you will want to close out of the browser and open it up fresh and sign in to the Portal or your email with that new password.