VPN Drops After an iPhone Dual-SIM Switch? Check the Data Line

Record voice and data lines separately

Apple describes one cellular-data network in use at a time. In Cellular or Mobile Data settings, inspect the selected data line rather than inferring it from Primary/Secondary labels or signal bars. SIM arrangements, menus and available functions depend on model, region and carrier.

Change one variable for comparison

1. Record iOS version, data-line label and selected VPN route without disclosing the full phone number.
2. When it will not disrupt important calls and data charges are understood, turn off Wi-Fi temporarily and test one ordinary page on the selected line.
3. Record the original Allow Cellular Data Switching setting before any comparison; changing it can affect data availability during calls.
4. Keep the VPN route unchanged and compare before and after a data-line change. Note whether ordinary internet stops before the VPN reconnects.
5. Restore the required voice/data settings. If only one line lacks ordinary internet, ask the carrier about service and plan conditions instead of deleting the eSIM.

Do not infer a product compatibility promise

A changed data line can change the underlying access network, so observe the new connection result. This is not a claim that Yunbao supports SIM bonding, seamless switching or a specific roaming plan. Report networks, timing and errors before and after the switch.