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 ('41cf35cb2caa73d7a9c6138f9ceac157', -1, 1529873308, 1529873308, '36e05bf6', 36, 0, 0)

Line : 187
File : sessions.php