phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO forum_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('8419eba58a7349d90fd098c031905a4f', -1, 1540272821, 1540272821, '365057a6', -2, 0, 0)

Line : 187
File : sessions.php