We are operating an online book store on shopify, https://asiapacbooks.com, and lately we have been receiving multiple feedback from customers across the globe who were unable to process their checkout.
When affected customers submitted their billing information, they were either getting (screenshots attached below):
1) Not Found error page
2) Parallels page (which I am not sure what is it about)
From my understanding so far, these reports are irregular, random, and intermittent. Some users were able to finally check out after multiple re-attempts, while there were a minority who encountered no issues whatsoever.
Please do advise on what can I do to resolve this issue, as it is posing quite the big headache for us at the moment. Thank you!