phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'a4c47d7cee7478fafc7f91d168838c9d' 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 ('a4c47d7cee7478fafc7f91d168838c9d', -1, 1770447811, 1770447811, 'd849d88f', -4, 0, 0)

Line : 187
File : sessions.php