Sharing SCREEN often, not-always, not-possible : impossible to use, often not-always, TeamViewer

Sametime on tablet with kitkat-android, when I run the latest version of TeamViewer-Q I can work on it ... Sametime no

I can't always use the Host version: isn't it the same?

... But what are the "when" conditions / parameters can I use TeamViewer normally?

For remote control I use Android-9 or Windows10 on 3G / WiFi ... The result is always unpredictable!

I await your suggestions or ideas