403. That’s an error.

Your client does not have permission to get URL /api/manifest/dash/requiressl/yes/source/youtube/id/99c60063d74e0ecf/itag/0/ei/CUHmXK-8I8Wb1wa0yqzYBg/playback_host/r4---sn-aigl6ney.googlevideo.com/mm/31%2C26/mn/sn-aigl6ney%2Csn-25glen7y/ms/au%2Conr/mv/m/pl/64/hfr/all/as/fmp4_audio_clear%2Cwebm_audio_clear%2Cwebm2_audio_clear%2Cfmp4_sd_hd_clear%2Cwebm2_sd_hd_clear/initcwndbps/358750/mt/1558593660/fvip/4/ip/2a03%3Ab0c0%3A1%3Ad0%3A%3Abda%3A1/ipbits/0/expire/1558615401/sparams/ip%2Cipbits%2Cexpire%2Crequiressl%2Csource%2Cid%2Citag%2Cei%2Cplayback_host%2Cmm%2Cmn%2Cms%2Cmv%2Cpl%2Chfr%2Cas%2Cinitcwndbps/signature/2EAC9101DCF2608536A13D5E18B7B76D226AE14B.D5B4D4161CA807D0D345452F130BC72D392753C6/key/yt8 from this server. That’s all we know.