phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'c6a6c5480eb664eb7c742bf4405f4c6f' 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 ('c6a6c5480eb664eb7c742bf4405f4c6f', -1, 1770992881, 1770992881, 'd849d809', -4, 0, 0)

Line : 187
File : sessions.php