The reason you are getting this error is because you do not have a Bitcoin or Bitcoin Cash wallet installed on your computer or mobile device. If you do not have a bitcoin wallet installed, your device/computer will not know how to handle the bitcoin: or bitcoincash: URI.
To complete the payment, you can scan using your wallet or copy and paste the payment details into your web wallet. View our guide to these other ways of paying an invoice.
For assistance with choosing a wallet to install on your device, please view our compatible wallets list.