From “Youtube official dev blog” :
UPDATE 06/03/15: Starting today, most YouTube Data API v2 calls will receive 410 Gone HTTP responses.
So this plugin must be update to new youtube api.
Same issue here. This post https://wordpress.org/support/topic/pl-id-not-accepted?replies=2 seems more focus on the “Gone” error message.
I have the same issue. I used this plugin without issue since months. Today I have the same error message. The playlist is still existing in youtube.
Any idea ?
