KnowRoaming is a pre-paid service. If you arrive abroad and switch onto the KnowRoaming network with no funds in your account, your service will not work. So it's best to top up your balance before you depart your home country.
Go into the KnowRoaming App > Select Load Account > Load Balance > Select Amount and Load Now
You have the option to automatically Auto-Reload your account to ensure that you always have enough credit in your account to keep your service active:
Go into the KnowRoaming App > Select Load Account > Configure Auto-Reload > Select Amount and Enable Auto-Reload
In the KnowRoaming App, you can monitor your balance and your usage. When you notice that your balance is below $5, it's recommended to top up your account to ensure that your service is not disrupted.