Hello,
Since you can't see any log from the HikaShop Payment log, the message should be generated by StripeJS.
Which means that the Stripe server communicates with the client (the javascript) and send the error, which cannot be catch by the plugin since it does not go through your server (which is in a way the security behavior of StripeJS).
And since the issue cannot be reproduce with the test account, it's more difficult to perform analysis.
We can hope that the JavaScript lib will display some content in the browser console.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.