Missing formula in work center &

What causes this issue?

In routing or network &V4&, you have entered the standard value &V2&
for operation &V3&. Operation &V3& is performed at work center &V1&.
Based on the formula in the work center and the standard value in the
operation, the system computes how much activity is expected for the
activity type. This activity is valuated on the basis of the activity
prices in cost center accounting to calculate the planned costs for the
operation.
In the case at hand you have not entered a formula in work center &V1&
or you have deleted the formula in work center &V1&.

System Response

The system cannot calculate the planned costs for operation &V3&
because you have not entered a formula in the work center.

How to fix this error?

Check the master data for work center &V1&. Specify a valid formula for
cost center assignment.
Make sure that the formula you select contains parameters that take
standard value &V2& into account.

Error message extract from SAP system. Copyright SAP SE.