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 ('25362e5113791d6f01aaab701e02667a', -1, 1540158455, 1540158455, '3691534f', 5, 0, 0)

Line : 187
File : sessions.php