403. That’s an error.
Your client does not have permission to get URL /videoplayback/id/a5f12010f5402bdd/itag/37/source/gfp_video_ads/requiressl/yes/acao/yes/mime/video%2Fmp4/ip/0.0.0.0/ipbits/0/expire/1480522673/sparams/ip,ipbits,expire,id,itag,source,requiressl,acao,mime/signature/9B03837CD032D91CFD74989E2A0A2A929BF30E6F.11A86A4A2A2A9AF6E35D1EE56341CF6506110D19/key/ck2/file/file.mp4
from this server. That’s all we know.