Sending an ACME HTTP validation request to serial-club.ru results in an unacceptable redirect. This is most likely a misconfiguration of your web server or your web application.
Bad port number provided when fetching https://serial-club.ru:/.well-known/acme-challenge/letsdebug-test:
Trace:
@0ms: Making a request to http://serial-club.ru/.well-known/acme-challenge/letsdebug-test (using initial IP 212.8.246.33)
@0ms: Dialing 212.8.246.33
@158ms: Server response: HTTP 301 Moved Permanently
@158ms: Received redirect to https://serial-club.ru:/.well-known/acme-challenge/letsdebug-test
A test authorization for serial-club.ru to the Let's Encrypt staging service has revealed issues that may prevent any certificate for this domain being issued.
Fetching https://serial-club.ru:/.well-known/acme-challenge/4PO0pa6Jofo8QZmvIJZZCb-3OcKSFlawmOh8GKWnhWE: Error getting validation data