phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '4a4137d8abd5450068ff3072c900806e' 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 ('4a4137d8abd5450068ff3072c900806e', -1, 1414250266, 1414250266, 'adf536d8', 15, 0, 0)

Line : 245
File : sessions.php