Not possible to block all rebate arrangements (see long text)

What causes this issue?

One or more rebate arrangements are currently blocked by another user.
Note that rebate arrangements from SD (Sales and Distribution) - which
are not actually relevant to this function - may be involved here.

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?

You can still carry out the retrospective compilation of the supplier
business volume. Respond to the confirmation prompt with <LS>Yes</>.

Error message extract from SAP system. Copyright SAP SE.