Failed to establish a new connection

[kientv]

I get some error log when deploy on k8s

1. [error] 23#23: *15 "/etc/nginx/html/index.html" is not found (2: No such file or directory)

2. [17/Aug/2022:17:30:22 +0000] "GET /.well-known/acme-challenge/ HTTP/1.1" 403 571 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.5005.136 Safari/537.36" "-"`

3. kubectl exec -it letsencrypt-helper-deployment-7857c9c849-fdfkn -- bash -c 'EMAIL=myemail@gmail.com DOMAINS=mailserver.[mydomain].vn ./fetch_certs.sh'

W0818 00:49:02.397107  786577 gcp.go:120] WARNING: the gcp auth plugin is deprecated in v1.22+, unavailable in v1.25+; use gcloud instead.
To learn more, consult https://cloud.google.com/blog/products/containers-kubernetes/kubectl-auth-changes-in-gke
Saving debug log to /var/log/letsencrypt/letsencrypt.log
An unexpected error occurred:
ConnectionError: HTTPSConnectionPool(host='acme-v01.api.letsencrypt.org', port=443): Max retries exceeded with url: /directory (Caused by NewConnectionError('<requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7fd8b72d2350>: Failed to establish a new connection: [Errno -2] Name or service not known',))
Please see the logfiles in /var/log/letsencrypt for more details.
command terminated with exit code