Cannot download App's from App Store. Youtube App in particular.

Question edited for clarity.

There is a rather 'round about' way of doing it and it starts with your computer!

Installing Apps using APK Installer on my Sinotec TV Home screen

• Open your browser on your computer, find the APK file you want to download, and select it.
• Once the App is downloaded, open Downloads, right-click on the APK file, then save to USB or external storage device.
• To install this APK from your storage device to the TV, plug the USB into the TV.
• On your HOME screen, go to APK installer, and select the APP you would like to install
• The app will begin installing on your device.
• After the application has successfully been installed the user can run the app with no issues.
• Please Note: Only selected smart models have the "Install APK" function.

https://www.sinotec.co.za/support/faqs/

Specs for your television says it comes with

• Netflix
• YouTube
• Twitter
• Facebook
• Mirashare
• Digital Dvb-T2
• Child Lock

Sinotec 58" UHD Android TV

Sinotec https://www.sinotec.co.za > product > sinotec-58-uhd-...
Open Browser: Yes; Prime Video: Yes; Netflix: Yes; DSTV Now: Yes; Showmax: Yes ... STL-58G50UM. Sinotec 58? UHD NETFLIX LED TV. Resolution: 3840 x 2160. View ...

..

What TV?
You will need to have a smartTV that supports the service, or use a computer, or use an outboard streaming device
https://help.disneyplus.com/csp?id=csp_article_content_international&sys_kb_id=eac89167db3048900a2af56e0f96193b

Desktop Web Browsers (via streaming)
Disney+ desktop browser system requirements
Mobile Devices and Tablets (via free downloaded app)
Android phone and tablet
Apple iPhone and iPad
Smart TVs (pre-installed or via free downloaded app)
LG WebOS Smart TVs
Samsung Tizen Smart TVs
Android TV Devices
Set-top Boxes and Game Consoles (via free downloaded app)
Apple TV (4th Generation and later)
Sony PlayStation 4
Roku
Xbox One
Other Streaming Devices (via free downloaded app)
Chromebook
Chromecast
Apple AirPlay
Amazon FireTV

1. 1 Verify that your Vizio Smart TV is connected to the Internet using a wireless or wired connection. An Internet connection is required to add and install new apps.
2. 2 Power on your television and press the "V" button on your remote. This will access the App Bar.
3. 3 Use the arrow keys on your remote to highlight either the Yahoo TV Store or CTV Store. Your options will vary depending on the model of your Vizio Smart TV.
4. 4 Press "OK" to launch the app store. A list of all available apps will display on-screen.
5. 5 Browse through the app store to find the app you want installed on your television. Examples of app categories you can choose from are Videos, Games, Sports, Lifestyle, Education, and more.
6. 6 Highlight the app you want added to your Vizio Smart TV, then press "OK."
7. 7 Use the arrow keys to highlight "Install App," then press "OK."The app will begin downloading, and display on the App Bar when complete. http://schematicscom.blogspot.com/
   http://elektrotricks.blogspot.com/
   http://electrotechnician.blogspot.com/
   http://electronicshelponline.blogspot.com/
   http://homenol.blogspot.com/
   http://remotesearch.blogspot.com/
   Please visit these sites to get some details./

If you look at your app store, there are a lot of people complaining about it. Better to ask support direct to then.

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