2022-09-13 23:59:58 I see such a response to a request by url
https://api.checkbox.in.ua/api/v1/receipts/sell<html>
<head><title>403 Forbidden</title></head>
<body>
<center><h1>403 Forbidden</h1></center>
<hr><center>nginx</center>
</body>
</html>
Also on this day, I see just thousands of requests from you in their api (I sent a minute cron, everything ended with errors {"message": "Change not vodcrito"}), most likely your box was banned in this ip or by the authorization key.