phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO zagataphpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('025312a4456cdecf4f95185559ce2bc8', -1, 1495557556, 1495557556, '36a22c69', 1, 0, 0)

Line : 187
File : sessions.php