Explanation (fault string): &1&2&3&4

What causes this issue?

'FaultString' element of error message: Contains an explanation for the
fault that can be read by users.

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?

If the fault string states "The transmission has been rejected because
the document has been sent by a non-certified transmitter or has not
been signed," you can probably solve the problem by (re-)importing the
transmitter certificate (see the Customizing activity
<DS:SIMG.PY_CH_RPUELMC_TCI>Import transmitter certificate</>).
If necessary, also check whether the stored URL for the distributor is
correct in particular with regard to the ELM version used.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.