How do I used Anti-Tracking for email? I am totally confused

I am using Chrome browser. I click on the Anti-tracking icon in the email. I select the mask and it is inserted to the email field. However, after I enter my password and click login, it says I have entered an invalid email address. What am I doing wrong?

fwiw ~
Set up Private Email in Norton AntiTrack here

Configure email masks in Private Email here

Fix email issues appearing in Private Email here

Fix Autofill errors in Private Email here

Norton AntiTrack’s Private Email supported browsers here


Features of Private Email here

Caveat: I do not run Norton AntiTrack nor Private Email