Check /etc/pihole/white.list or /etc/pihole/whitelist.txt for the contents and make sure it is there. Also check if the domain is showing the the admin page logs as not blocked. If the domain is there and not being blocked then you need to find the domain being blocked.
From your description it looks like the bit.ly domain may be blocked since that is where the browser will go first to get the redirect.
But as msatter finds, I don't think this is the domain you want.