If you're receiving a transaction error when settling, for example, your transaction logs say something like Program 9xQeWvG816bUx9EPjHmaT23yvVM2ZWbrrpZb9PusVFin failed: custom program error: 0x1000772, then check the Referrer Quote Wallet in the explorer. If should be an SPL token account for the quote currency. If it is not, e.g., it's a SOL address, then the GUI you're using is invalid, and you should switch to a new one.