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 ('ea4e45feb75d2c4ba6526f93f002e97e', -1, 1529637950, 1529637950, '36a2a59e', 2, 0, 0)

Line : 187
File : sessions.php