Transportation lane &1: Piecewise linear cost function not considered

What causes this issue?

For transportation lane &V1&, you specified that a non-linear cost
function be used for the number of vehicles included on this lane. This
constraint cannot be considered by a continuous solution method.

How to fix this error?

If possible, choose a linear cost function. If you need non-linear cost
modeling, choose a discrete solution method in the SNP optimizer
profile (this might increase runtime).

Error message extract from SAP system. Copyright SAP SE.