phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO sajjad_bbsessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('9774c6b207611d69218e2fe7083791e6', '1', '1513538884', '1513538884', '36537ae3', '123', '0', '0')

Line : 207
File : sessions.php