Master Routing Issue

Hi all

I hope everyone is well.

We make use of master routings linked to various manufactured items using item cross reference but recently when generating a manufacturing WO and attaching the routing and parts list, we get the following error:

"Subject : Error: Routing not found

CAUSE . . . . No routing found for the item or operation sequence number.

RESOLUTION . . Either change the item to one that has a routing, or change

the operation sequence number to one that exists on a routing."

I have checked for a valid item cross reference, valid master routing, master routings is activated in manufacturing constants, branch/plant constants looks fine, etc. This occurred randomly and I am not sure what else to check?