Material & does not exist in plant &. Purchase order possibly incorrect

What causes this issue?

During pegging the program found a material that has not been defined
in the material master for the plant.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check whether there are any purchase orders (possibly containing a
faulty material) on hold. There may be a faulty material in a
replenishment object.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.