ORA-01775: looping chain of synonyms

Cause: Through a series of CREATE synonym statements, a synonym was defined that referred to itself.

Action: Change one synonym definition so that it applies to a base table or view and retry the operation.

For example, the following definitions are circular: CREATE SYNONYM s1 for s2;
CREATE SYNONYM s2 for s3
CREATE SYNONYM s3 for s1
or
CREATE SYNONYM s4 for s4

Check your synonyms with:
select * from all_synonyms where synonym_name = ‘name’ or table_name = ‘name’;

SELECT table_owner, table_name, db_link
FROM dba_synonyms
WHERE owner = 'PUBLIC'
AND synonym_name = <<synonym name>>

select owner, synonym_name, connect_by_iscycle CYCLE
from dba_synonyms
where connect_by_iscycle > 0
connect by nocycle prior table_name = synonym_name
and prior table_owner = owner
union
select 'PUBLIC', synonym_name, 1
from dba_synonyms
where owner = 'PUBLIC'
and table_name = synonym_name
and (table_name, table_owner) not in (select object_name, owner from dba_objects
where object_type != 'SYNONYM')