phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'acdbf891ca746589bf4f5c5e7c580a91' 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 ('acdbf891ca746589bf4f5c5e7c580a91', -1, 1768642958, 1768642958, 'd849d879', -4, 0, 0)

Line : 187
File : sessions.php