If you are using release approval levels, enter the subworkflow

What causes this issue?

You want to use release approval levels but have not entered a
subworkflow for the amount release.

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?

Specify the subworkflow for the amount release or do not use release
approval levels.

Error message extract from SAP system. Copyright SAP SE.