Business activity not ended for business partner &1; see long text

What causes this issue?

You want to block data related to business partner &V1&. The business
activity for business partner &V1& has not ended.

System Response

The system cannot block the data for this business partner.

How to fix this error?

Check the pending business activities in relation to this business
partner in the applications that use this data. Data can be blocked as
soon as the business activity has ended.

Error message extract from SAP system. Copyright SAP SE.