phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '5c88db438b66a140fe7c91b9fe6ad351' 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 ('5c88db438b66a140fe7c91b9fe6ad351', -1, 1430017461, 1430017461, '3692aedc', -4, 0, 0)

Line : 187
File : sessions.php