Source system &4, target system &1, channel &2, blocked by user &3

What causes this issue?

qRFC monitoring has determined that user &V3& has initiated a transfer
of data from system &V4& to system &V1& using queue &V2&. This transfer
led to an application error.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

All subsequent entries using the same queue are blocked as long as the
incorrect entry remains in the queue. If a queue is blocked over a long
period, planning in APO does not take place with current data.

How to fix this error?

Procedure for System Administrators

Start transaction 'SMQ1' (qRFC monitor) in system &V4&
Look for queue name CFEP3024,
Select the row
Choose "Display selection F7"
Select the first row
Choose "Select F2"
Copy the ID from the TID column to the clipboard
Open the transaction SLG1 in the target system
Insert the ID in the "external number" field
Execute the transaction
You receive the relevant error messages in the subsequent screen.
Remove the cause of the error, or delete the entry in the qRFC monitor.
<ZH>Warning</>: Permanent inconsistencies may result if you delete
entries.

Error message extract from SAP system. Copyright SAP SE.