A candidate cannot be forwarded to another requisition. A message stating 'The candidate's data privacy selection is "Only recruiters managing jobs I apply to" so you cannot forward the candidate to any job requisition' is appearing.
SAP SuccessFactors Recruiting Management
This is an expected behaviour. The candidate has set up their privacy options so that they can only be seen by recruiting users on jobs they have applied to. Since you would be forwarding them to a requisition they haven't applied to then this would go against their privacy settings.
forward candidate, privacy, recruiter, dpcs, requisition , KBA , LOD-SF-RCM-CAN , General Candidate Issues (not Offers, not Profiles) , LOD-SF-RCM-CAP , Candidate Profiles , Problem