I have seen a few of these now on subscriptions with a successful checkout. There are not many, maybe 10 in the last 200 subscriptions, but still there seems to be some sort of problem.
Below is an x-payment connector error for the same time as the latest "not created".
[05-Jun-2018 20:55:51] xpay_connector message:
Process callback data. Transaction id is not found
Request URI: /store/payment/cc_xpc.php
However, I get this error showing up in the logs a number of times (30 in the last 400 orders).
If I were to guess, it is that the when one of the above errors happens and it is for a subscription, that is the cause of the "not created". Though I am not sure.
Any ideas on why this error is happening? Some timeout or something I have set too low on my server? X-payments is hosted, but xcart is on my own server.