Please ensure that your balance is sufficient in the loyalty program you are trying to deduct from. It's also a good idea to check that you have fully registered your program and are seeing no errors in the Loyalty Wallet section (aka you can see your updated balance).
You may also be running into trouble because of restrictions related to your reward program. The Points Loyalty Wallet will let you know via a message when you try to complete a transaction if this is the issue.
If you're still having trouble, please get in touch using the links on the right side of this page.