If your card does not have any data package or that the data package does not cover your current location, then you will not be able to connect to the network.
You will be able to check in the MOGO APP if you have any available data package ready for use.
This is how to check the details of your current data packages.
Go to MOGO APP > Home > MOGO S data package Details
If your MOGO S card does not have any data packages available for use, it will show the following page below. Please tap the "purchase package" option to purchase data package for your MOGO S card.