Dear Manish Karn,
Our lookup.dbpedia.org was running under the same dbpedia.org server. I need to check with our staff but it looks like there were a server migration and lookup was not migrated.
You have two options from now (until we have more info about the server migration):
Thank you so much! I used the second option. I hope it keeps working at least for 24 hours from now.
It will. Wish you luck in your demo