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 ('4fb2e828d4d6d16f2882b3b16880c8f1', -1, 1534873765, 1534873765, '36c42a08', 5, 0, 0)

Line : 187
File : sessions.php