Most "no service" cases come down to one of five small things. Try these in order.
1 · Toggle Airplane Mode
Turn Airplane Mode on, wait 10 seconds, turn it off. This triggers a full network re-scan and is the single most effective fix.
2 · Check the data line is correct
On iPhone: Settings → Cellular → Cellular Data — make sure your travel eSIM is selected (not the home SIM). On Android: SIM manager → Mobile Data → travel eSIM.
3 · Enable Data Roaming on the travel line
Yes — for your TRAVEL eSIM, Data Roaming should be ON. Keep it OFF on your home line. This often gets confused.
4 · Restart your phone
A clean restart resolves stuck carrier-profile registrations. Power off completely, wait 30 seconds, power back on.
5 · Re-install the eSIM
If none of the above works: delete the eSIM (Settings → Cellular → tap the eSIM → Remove eSIM) and re-install it using the QR code from your purchase email.