SIH object web service error "Record does not exist"

SUGGESTED

We have a customer that is getting a error that other customers are not seeing.  We have a simple web service to pull a Invoice.  The web service reads object SIH.  We pass in the appropriate xml to pull a Invoice...


<item><key>NUM</key><value>INV000027</value></item></objectKeys>

But we always get a error  "Record does not exist".  The invoice is in table SINVOICE, and the Inv is posted. 

Customer is using X3 V9 P3