No additional posting to asset

What causes this issue?

A downpayment was already posted to the asset &V1&
&V2& in the currently displayed document. Additional posting to the
same asset in this document is not possible for technical reasons.

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?

Combine the two downpayments into one.

Error message extract from SAP system. Copyright SAP SE.