phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'd638cf3893873a0154e90bb2167ee133' 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 ('d638cf3893873a0154e90bb2167ee133', -1, 1419273829, 1419273829, '17170cca', -4, 0, 0)

Line : 187
File : sessions.php