Hello,
You'll find other rhreads about Stripe V3 (which is not related to the HikaMarket support).
These are the common issues :
1 - no https for the checkout/website
2 - wrong credentials
Since it's rhe Stripe JS from the Stripe website which set-up for payment form, you can't have logs in HikaShop payment log. But if you open your brwser consile, you shoukd have some message coming from Stipe directly.
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.