Orders keep failing

On this staging site https://staging.arlorx.com/checkout/ the orders do not go through even with all other plugins inactive and the theme also set to default.

Here is a video of the issue on the staging site: https://tinyurl.com/2897nc2z

The same is also seen on the production site ( arlorx.com ): https://tinyurl.com/23dsyze2

The orders go through fine using COD etc. Please let me know a solution for the same.

The page I need help with: [log in to see the link]