Sounds like the cert is missing a required SAN name. I used namecheap and Let's Encrypt together before. I had to ensure that *.ziviz.us
and ziviz.us
were both provided to certbot. I used manual DNS challenges, and it looked like this:
certbot certonly --manual --preferred-challenges dns
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Please enter the domain name(s) you would like on your certificate (comma and/or
space separated) (Enter 'c' to cancel): ziviz.us *.ziviz.us