phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '0' 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 ('5d2dbdcb9c06ac539a027466640d56b9', -1, 1548141676, 1548141676, '36ea4b90', 2, 0, 0)

Line : 187
File : sessions.php