phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('e344aff2665f786c30c5c6005dd4e9f0', -1, 1462416493, 1462416493, '36c4f691', -1, 0, 0)

Line : 187
File : sessions.php