phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : -1 ERROR: duplicate key value violates unique constraint "phpbb_session_pkey" DETAIL: Key (session_id)=(09cf39478874d8cb5841a07d293e0a5f) already exists.

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('09cf39478874d8cb5841a07d293e0a5f', -1, 1493563733, 1493563733, '36c6496f', 3, 0, 0)

Line : 188
File : sessions.php