If the Samsung device connects to a foreign or foreign network, no data packets are sent until data roaming is activated, and only when raoming has been activated is the Internet available on the foreign network, which can lead to additional costs.

Android 10 (One UI 2.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Connections
Step 3:  Tap on  Mobile networks
Step 4:  Enable or disable  Data roaming
  1. Open the Settings
  2. Tap on Connections
  3. Tap on Mobile networks
  4. Enable or disable Data roaming

Samsung Instructions