You need to determine early in the project if you are launching a global or region-specific product.
A common issue when developing a cellular Internet of Things (IoT) application is not being able to connect to the network, even if LTE-M or Narrowband Internet of Things (NB-IoT) is supported in the area according to the Mobile IoT Deployment Map. This is usually because the Subscriber Identity Module (SIM) card does not have a Low-power Wide Area Network (LPWAN) subscription or it is not supported by the Mobile Network Operator (MNO) in that area. For example, using a roaming SIM card that does not have an agreement set up with that MNO. It is important to note that MNOs differentiate between standard IoT 2-4G SIMs and LPWAN SIMs, where the latter is needed for LTE-M/NB-IoT connections. An example is the two versions of Vodafone Global IoT SIM cards, 4G with IMSI 20404 and LPWA with IMSI 901288.
You need to use the correct SIM card to get connected. Nordic Semiconductor ships all their nRF9160 Development Kit (DK)s and Nordic Thingy:91™ prototyping platforms with an iBasis SIM roaming card that can be used in these areas. If your country is not on this list, you would either need to get a local SIM card or a roaming SIM card from another provider.