phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('872ef5ce801146a40e71800a700c7717', -1, 1472061443, 1472061443, '36a2d543', -1, 0, 0)

Line : 187
File : sessions.php