Web Site: Manage Settings for FiOS Digital Voice

[#1]

Every time I try to access the Manage Settings button under FiOS Digital Voice the response page tells me:
Alert
The account information entered is no longer valid as this account has been deleted
please verify your Verizon Online Username or use a different Verizon Online Username to access FiOS Digital Voice services.
    Sign in with a different account

I am already logged into our one and only account.

What is wrong?

[#2]

I had that my first time signing in,   I just simply hit sign in again and used the same info and it logged me in on try TWO.

Did you try that, or is it an endless loop for you?  

and are you using your FiOS Email address?

[#3]

Thanks for the response Hubrisnxs.

Well, I tried using the Sign in with a different account link (provided in the Alert message) and used my normal account credentials.

I received a fraud alert/monitoring popup agreement and clicked OK to accept.

The Verizon progress bar appeared (like it was loading my account info).

When it finished I ended up on a FiOS Digital Voice selling points and how to order page:

https://www36.verizon.com/FiOSVoice/GetFiOSVoice.aspx?SETTOPARENT=TRUE

In answer to your question, I've been in our Verizon email before, but we simply have it set to forward to another (non-Verizon) account.