phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'b9f87b2fa27169a37f25cb4e62251e73' 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 ('b9f87b2fa27169a37f25cb4e62251e73', -1, 1770546496, 1770546496, 'd849d88f', -4, 0, 0)

Line : 187
File : sessions.php