phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '21b18f5df6a4912e2779e45312410217' for key 'phpbb_sessions.PRIMARY'

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('21b18f5df6a4912e2779e45312410217', -1, 1770486485, 1770486485, 'd849d88f', -4, 0, 0)

Line : 187
File : sessions.php