nas.mr-kryuchkov.ru has an A (IPv4) record (46.147.189.78) but a request to this address over port 80 did not succeed. Your web server must have at least one working IPv4 or IPv6 address.
A timeout was experienced while communicating with nas.mr-kryuchkov.ru/46.147.189.78: Get "http://nas.mr-kryuchkov.ru/.well-known/acme-challenge/letsdebug-test": context deadline exceeded
Trace:
@0ms: Making a request to http://nas.mr-kryuchkov.ru/.well-known/acme-challenge/letsdebug-test (using initial IP 46.147.189.78)
@0ms: Dialing 46.147.189.78
@10000ms: Experienced error: context deadline exceeded
A test authorization for nas.mr-kryuchkov.ru to the Let's Encrypt staging service has revealed issues that may prevent any certificate for this domain being issued.
46.147.189.78: Fetching http://nas.mr-kryuchkov.ru/.well-known/acme-challenge/ni63vzsWuK0d5KQTed5CuUyTQGgk4IEpbJ5eOwu_l3A: Timeout during connect (likely firewall problem)