Inbound queue &2 (target system &1) blocked by user &3

What causes this issue?

qRFC monitoring has determined that user &V3& has initiated a data
transfer to target system &V1& via inbound queue &V2&. This transfer
resulted in an application error.

System Response

As long as the entry with errors remains in the queue, subsequent
transfers using the same queue will also be blocked. If a queue is
blocked for an extended period of time the planning in the target
system will be carried out with data that is out of date.

How to fix this error?

The data transfer using inbound queue &V2& can only be continued once
the error has been rectified. You need to analyze the cause of error,
rectify the error and restart the queues. The exact procedure is
described under "Procedure for system administration".

Procedure for System Administrators

Analyze the error using the application log for the queue containing
the faulty entry. To display this application log, you can use the
following procedures:
You can execute error analysis using the
<DS:REPN./SAPAPO/RCIFQUEUECTRL>SCM Queue Manager</> and go from there
directly to the relevant application log.
You can search for the relevant application log using transaction ID
(TID) &V4&.
For more precise error analysis start transaction SLG1 in target system
&V1&. Enter the ID &V4& in the 'External identification' field. Execute
the transaction. The application log for this faulty queue entry is
displayed.
If a value for the TID is not contained in the error message, you can
find this value using the qRFC monitor:
Call the qRFC monitor for outbound queues in system &V4& (transaction
SMQ1).
Select the line containing queue name &V2&.
Choose <ZK>Display Selection (F7)</>.
Select the first row and choose <ZK>Choose (F2)</>.
Copy the value (GUID) from the <ZK>TID</> column to the clipboard.
Call the <ZK>Analyze application log</> screen in target system &V1&
(transaction SLG1).
In the <ZK>External ID</> field, enter the TID from the clipboard.
Execute the transaction. The following screen contains the relevant
error messages.
If navigation to the application log from the qRFC monitor for CIF
queues is set up in your system, you can go directly from the qRFC
monitor to the relevant application log. In system &V4&, navigate in
the qRFC monitor for outbound queues (transaction SMQ1) to the row
containing queue name and the <ZK>TID</> field. If you double-click the
<ZK>TID</> field, the relevant application log is displayed.
If this message was generated in SAPScript (SCR) format, you can find
the TID value at the end of the message. Copy this value and proceed as
described above to display the application log in target system &V1&.
Rectify the cause of the error or delete the entry.
<ZH>Note</>: Deleting entries can lead to data inconsistencies. For
more information, see SAP Note 524419.
The qRFC alert issues an email for the first faulty queue entry, but
not for subsequent faulty entries (depending on the settings made). You
should therefore check whether other faulty queue entries exist.
Note also that application logs may not be created in the target system
for all errors in the data transfer. For example, if a program
termination (short dump) occurs in the target system, the error must be
investigated in target system &V1& using dump analysis (transaction
ST22). A comparable example is the error message 'Screen output without
connection to user'.
For more recommendations about error analysis, see the Integration
Troubleshooting Guide R/3 - APO. SAP Note 393763 describes how you can
find this in the SAP Help Portal.
For more information on the different queue statuses, see SAP Note
378903.

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

Error message extract from SAP system. Copyright SAP SE.