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 ('8ca16fe45a95571eb8d18e997544f2b2', -1, 1490442059, 1490442059, '3691d0a0', -9, 0, 0)

Line : 187
File : sessions.php