I’m trying to renew a certificate and I can’t stop getting this message:
Attempting to renew cert from /etc/letsencrypt/renewal/mail.ex-nihilo-paris.com.conf produced an unexpected error: Failed authorization procedure. mail.ex-nihilo-paris.com (http-01): urn:acme:error:connection :: The server could not connect to the client to verify the domain :: Fetching http://mail.ex-nihilo-paris.com/.well-known/acme-challenge/fb9D3S51twTLKeGSIuTWD1VPdVM5Pzxv7ixrE3mTNHM: Timeout. Skipping.
I double checked there was no issue with the domain (it’s a production domain, accessible from everywhere), no firewall issue (port 80 is opened). The authenticator is standalone and opens a listining socket (I can see 0.0.0.0:80 opened by a python process while waiting for the challenge response).
Could you please tell me what could go wrong? Is there another way to renew the certificate, it expires in 3 days (I had to wait for holidays as our office is closed to renew the certificate).