phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '988760b5ce56482ea3d69f50a301b53e' for key 'PRIMARY'

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('988760b5ce56482ea3d69f50a301b53e', -1, 1495778141, 1495778141, '36a2a8bb', -1, 0, 0)

Line : 187
File : sessions.php