phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '421fda80b63d87c1c397bf35e74cf9cc' 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 ('421fda80b63d87c1c397bf35e74cf9cc', -1, 1770448897, 1770448897, 'd849d88f', -4, 0, 0)

Line : 187
File : sessions.php