Client in RFC destination & is & and not &

The client in the specified destination does not match the client where
the check was performed.

What causes this issue?

Incorrect configuration of SOAP Runtime

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?

Inform your system administrator of the error message number.

Procedure for System Administrators

For each client, SOAP Runtime requires a destination for technical
services. This destination must have the type "3" (ABAP connection) and
have a user of the type "Service", with an appropriate password, in the
settings for "Logon and Security". The "Client" field must also contain
an existing client. This destination must be entered in the central
configuration for the appropriate client.

Error message extract from SAP system. Copyright SAP SE.