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 ('507d2531850441c12c965e04acab98a3', -1, 1539782698, 1539782698, '36a285de', 2, 0, 0)

Line : 187
File : sessions.php