Surplus of product &1 at location &2

What causes this issue?

In time bucket &V3&, product &V1& at location &V2& has a surplus stock
of &V4&.

System Response

The optimizer was unable to find a solution without creating surplus
stock. Since the optimizer attempts to minimize the existing surplus
stock as much as possible, the solution calculated might have undesired
attributes.

How to fix this error?

Check whether the planned surplus and the solution found are acceptable.
Surplus stock might be due to the following:
The permissible stock upper limit chosen is not high enough: Increase
the upper limit.
There are fixed orders or opening stock levels that increase the
material stock at the location: Delete these fixed orders or opening
stock levels.

Error message extract from SAP system. Copyright SAP SE.