SAP Message CB621 - Cannot perform input check at the moment. Value must be rejected

Diagnosis According to the definition of characteristic &V1&, the input check isto be called in a remote system (RFC destination &V2&) and display thismessage in the case of an error. The RFC call returns the following error message: "&V3&&V4&". System Response The value you entered must be rejected. Procedure Wait until the remote system is available again or the error has beenfixed, and repeat your entry.