From my provider a got this message:
there is a problem with connection to youtube service
connect(11, {sa_family=AF_INET6, sin6_port=htons(80), inet_pton(AF_INET6, "2a00:1450:4001:c02::76", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28)
sendto(11, "GET /feeds/api/playlists/AF6tPnbBKi_g5xKLU8EycPzgIRwVLBpR?v=2&key=AF6tPnbBKi_g5xKLU8EycPzgIRwVLBpR&start-index=1&max-results=20&orderby=position&safeSearch=moderate HTTP/1.0\r\nHost: gdata.youtube.com\r\nAccept: */*\r\nUser-Agent: TubePress; http://tubepress.org\r\nHTTP-Version: HTTP/1.0\r\nAccept-Encoding: gzip;q=1.0, deflate;q=0.5\r\n\r\n", 328, MSG_NOSIGNAL, NULL, 0)
recvfrom(11, "HTTP/1.0 403 Invalid developer key\r\nX-GData-User-Country: PL\r\nContent-Type: text/html; charset=UTF-8\r\nContent-Length: 165\r\nDate: Wed, 08 May 2013 08:06:46 GMT\r\nExpires: Wed, 08 May 2013 08:06:46 GMT\r\nCache-Control: private, max-age=0\r\nX-Content-Type-Options: nosniff\r\nX-Frame-Options: SAMEORIGIN\r\nX-XSS-Protection: 1; mode=block\r\nServer: GSE\r\n\r\n<HTML>\n<HEAD>\n<TITLE>Invalid developer key</TITLE>\n</HEAD>\n<BODY BGCOLOR=\"#FFFFFF\" TEXT=\"#000000\">\n<H1>Invalid developer key</H1>\n<H2>Error 403</H2>\n</BODY>\n</HTML>\n", 16384, 0, NULL, NULL)
contact the tubepress author 