IDoc can be ignored - error during transfer from R/2 System

What causes this issue?

The IDoc was sent from an R/2 system. An error occurred during data
transfer. The R/2 system will send the IDoc again or has already sent
the IDoc again. This IDoc will therefore be assigned the status
'Ignore' and will not be processed further. Due to the status, the IDoc
can be reorganized.

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?

Error message extract from SAP system. Copyright SAP SE.