Hi guys,
I had a lot of problem with making Letsencrypt work with Zimbra so just created a small script for installing LetsEncypt certificate on Zimbra server. Hopefully It 's helpful.
You guys also can use this script to automatically renew your certificates.
Remember update your certbot to version that supports the --preferred-chain "ISRG Root X1"
Enjoy!
https://github.com/vietjovi/zimbra-util ... encrypt.sh