MS CRM Customer Journeys -Preference center

Question

I am using MS CRM Customer Journeys. I have configured everything, I had completed couple of rounds of testing already and it was working well.

Today suddenly the unsubscribe link stopped working and it is giving me error "HTTP Error 404 - Not Found". Can you please give me the possible solutions?

Only change I can count is - I changed the default brand profile to our own since I updated our domain DSN entries.

Thanks for your help.