How To Fix SO123 - A reply to the document has already been sent

SAP Error Message - Details

• Message type: E = Error

• Message class: SO - SAPoffice: message texts

• Message number: 123

• Message text: A reply to the document has already been sent

What causes this issue?

A reply to the document has already been sent.

System Response

How to fix this error?

You can send other replies to this document without using one of the
reply functions. However, these replies will not be recorded in the
correspondence history.

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.