Your IP keysets speak to each other 'peer-to-peer' in a manner of speaking, and the MBU is used to allow IP resources to talk to TDM resources.

If IP can't talk to TDM, something about your MBU isn't configured properly.

Verify the MBU IP address (static IP, different from LAN2 address) with proper subnet and gateway.

Double check slot and MAC programming. MAC adresses are easy to fat-finger.

Disconnect the MBU from the network and ping the MBU IP address to verify you don't have an IP conflict.

Sometimes the thoughts in my head get so bored, they go for a stroll through my mouth. This is rarely a good thing.