So today I tried to access the new site after it has changed since last Oct, to update the passport information.

I followed the instructions to create a new Login.Gov account, everything seemed fine - with the account seemingly established. However when it redirected me to the TTP site
https://ttp.cbp.dhs.gov/

its system threw me out of the logged in status, then I went thru the same log in process again, it took the credentials, produced the automatic phone call with the code, YET, after I entered that, it still threw me out to the beginning of the loop.

When I tried to access again using the email confirmation link (to verify the email address), it allows me to log in and see my profile, even logged the time I was logged in the TTP site but in effect, I was never really logged in - all I could see were some really quick flashes of redirect, then I was thrown out!

I cannot find anywhere there is related FAQ on this problem, nor there is a web support number to call.

Any suggestion on what else to try?

BTW, I have tried FF and Chrome, have cleared all the cache and history, even set FF to accept all cookies and tracking, to no avail - on a desktop with Window 8.1 - if that matters.