phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '947f982e1dcd5e510495db16cdd9947f' for key 1

INSERT INTO phpbb2_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('947f982e1dcd5e510495db16cdd9947f', -1, 1498349492, 1498349492, '36a2d3aa', 15, 0, 0)

Line : 187
File : sessions.php