Processing of message &1 stopped; message already in process

What causes this issue?

You tried to restart a message that is already in processing in another
session.

System Response

To avoid inconsistencies, the system stopped processing the message in
the current session.

How to fix this error?

Wait until the other session finished processing the message. After
that, try again in the current session.

Procedure for System Administrators

In some cases, restarting a message, for example, from the Monitoring
and Error Handling or the Message Summary, is not possible. The system
will continue to indicate that the message is already in process,
although the message is not processed in any session.
This might happen if a dump occurred. In such cases, transaction
<DS:TRAN./AIF/XML_RESTART>/AIF/XML_RESTART</>can be used to restart a
message.

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