Domain name not resolving to IP address

[Jack J]

Hi All,
I'm using 1&1 Dedicated sever and I've bought 8 static IP Addresses.
I've assigned these IP addresses to different domains via plesk and also via 1&1 Control panel.

All domains seem to work and resolve correctly to their respective IP Addresses except one.

I've checked all the settings but can't figure out why one domain is not resolving correctly?

Any clue?