phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'ac20a8aaddba7b6239fb2e07988ba668' 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 ('ac20a8aaddba7b6239fb2e07988ba668', -1, 1765360639, 1765360639, 'd849d8da', -4, 0, 0)

Line : 187
File : sessions.php