Error type: "Forbidden". Error message: "The provided API key has an IP address restriction. The originating IP address of the call (188.8.131.52) violates this restriction." Domain: "global". Reason: "forbidden".
Did you added your own Google API key? Look at the help
Check in YouTube if the id UUUftd_b30ID2qwrUX4naZ_Q
belongs to a playlist. Check the FAQ
of the plugin or send error messages to support