Youtube not playing on mobile data

For short answer go to bottom :)

I know this thread is old but a comment regarding tier 2 figuring out some third party blocking on their end sparked my memory. So my daughter has been complaining for months Youtube doesn't work when she isn't on WiFi.. no amount of clearing data/cache reinstalls and the problem continued even after she got a newer phone recently (how I came across this thread). When I saw the post above it sparked my memory that I had enabled parental controls/web filtering .. and sure enough I go into my account, go to her line and "Web Guard" was set to "High" which included the description below. I set it to "Medium" and waited about 30min and went to go check it again and it all started working… mystery finally solved.

Short answer:

Log into your T-Mobile account and look for “Family Controls” and then “Web Guard” and adjust filtering from High to Medium.

Web Guard High includes this description:

• Transmisión de video: transmisión de video en tiempo real, que incluye televisión por Internet, retransmisiones vía Internet y vídeos compartidos.