General issues, or "An error occurred. Please try again or contact our support"
To troubleshoot the problem, please reproduce the error and take a look into the WHMCS gateway log. The gateway log records all requests and responses made by the module, so it may contain useful information about the cause of the problem.
If you don't find any relevant entries in the gateway log, try enabling the module debug log and reproduce the error again. This may create a log entry with more detailed information about the issue.
By reviewing the logs, you should be able to determine the cause of the problem. If the error message is not clear, please provide the request and response in plain text. This will allow us to better understand the issue and assist in finding a resolution.
HTTP status 500
If the callback file is manually accessed via the browser, an error response will be output, and the HTTP status will be set to 500.
The callback file is not designed to be manually accessed. If it is, an HTTP status code of 500 is the expected response. For security purposes, only calls from Binance are permitted.
If a Binance callback results in an HTTP status of 500, it's likely that the webhook secret key is incorrect. In such a case, relevant information will be logged in the module debug log. However, please note that the module debug log will also contain entries regarding manual accesses of the callback file, which should be ignored.
Gateway log: "Binance headers missing. Ensure your server (or WAF, CDN, etc.) does not strip off HTTP headers"
The log entry means that the module did not find the necessary HTTP headers in the HTTP request. Either the callback file was manually accessed via the browser, or your server or a proxy in front of it removed the headers.
To solve the problem, the web server must be configured to pass all HTTP headers starting with "binancepay-" to PHP. With a default configuration, this is already the case, and many WHMCS payment gateways require custom HTTP headers to be processed in order to function properly.