That’s because TinyDB is a local database, same like sql lite,etc.., in which only your device can access the data you’ve stored in.
You need to use a Cloud Database to store your data, all of the devices can access it, a good examples for cloud databases are:
FireBase (RealTime database, but its free plan is very limited if your app has many users ) :
AirTable ( Quite easier and less limited but not realtime database ):
MySql, ( you will need to have a server to host MySql at, but it’s the best database if your app has a lot of data, as you create your own database with different limits according to the hosting site you host at. )
CloudDb (A realtime databse, that you’ll have to buy a redis server to host cloud db at, also, it’s an experimental component, so use it with caution):
Hope this help you 