"Authorization" header not found in Xsolla webhook request.

[wagishsharma]

Happens due to class WebhookAutheticator in function authenticateSignature:

//This checks for case sensitive key: "authorization"

 if (!array_key_exists('authorization', $headers)) {
            throw new InvalidSignatureException('"Authorization" header not found in Xsolla webhook request. Please check troubleshooting section in README.md https://github.com/xsolla/xsolla-sdk-php#troubleshooting');
        }

In my case I was getting the key "Authorization" (with capital 'A') in the header and it was throwing InvalidSignatureException.

Quick Solution for individual is to dump your headers and check for this key and make changes according.
A more permanent solution will be to read case insensitive header key to avoid this issue.