phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'f3fdc401480a2e55901d7bdd89385d5f' for key 1

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('f3fdc401480a2e55901d7bdd89385d5f', -1, 1418976216, 1418976216, 'b8496852', -4, 0, 0)

Line : 187
File : sessions.php