phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '8f21d91eec879ab116d85c6250cf4166' 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 ('8f21d91eec879ab116d85c6250cf4166', -1, 1770091444, 1770091444, 'd849d8a2', -4, 0, 0)

Line : 187
File : sessions.php