XI Error UPDATE.XICACHE: Queue stopped

Hi Experts,

In our Production System many messages are stuck in SMQ2 (Inbound Queue) due to "XI Error UPDATE.XICACHE: Queue stopped". I try to fix it by clicking the "Execute LUW's" button but the system is showing a message as "Function module does not exist or EXCEPTION raised".

Any idea what needs to be done to fix issue? Your help is highly appreciated.

Regards

Faisal