This can happen when attempting to add trust (connect a gateway), place an order or send an XRP transaction.
Please click here to read an article with background information on this situation.
To resolve this, you need to acquire more XRP on your Ripple account. You can either:
- Have someone send some XRP to you.
- Deposit some funds (e.g. BTC, ETH, EUR, or USD) and exchange these for some XRP.
- Use a 3rd party service like ShapeShift or Poloniex to purchase XRP and send it to your Ripple account.
Please note that to deposit funds (under 2.), you'll need to have a corresponding gateway already connected (which itself requires some XRP reserve). Also, to deposit USD or EUR you will need to have a verified account, which can be a lengthy process, especially when there are many new users at GateHub.