phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '51a9c8c0058db09f6e4c4917354ac3cf' 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 ('51a9c8c0058db09f6e4c4917354ac3cf', -1, 1763971477, 1763971477, 'd849d82b', -4, 0, 0)

Line : 187
File : sessions.php