target object for "<str>" can not be resolved

  Explanation:  A synonym chain is formed when synonyms  reference
  other  synonyms.   This error occurs that synonym chain has been
  broken using DROP SYNONYM ...   CASCADE  or  a  loop  is  formed
  because  ALTER  SYNONYM  references  a  target  synonym  already
  appearing in the chain.

  User Action:  This problem is detected during CREATE  and  ALTER
  SYNONYM.  This statement has failed, repeat the statement with a
  corrected synonym reference which avoids this error.