Sorry to bothered you !
Previous i have explained but now i do it more better, i have 2 sub domains, one is for mattermost and other is for nextcloud. Both name is like mattermost.xyz.com and cloud.xyz.com. Now i want to set letsencrypt for both sub-domains.
So which i performed steps for letsencrypt -
1- logged in admin pannel and went to server certificate.
2- click for letsencrypt certificates, and type sudomain in box “mattermost.xyz.com” and generated certificates successfully.
3- after same steps performed for other subdomain “cloud.xyz.com”.
4- now there are three certificates 1- self-signed and 2 letsencrypt certificates.
5- when i open in browser https://mattermost.xyz.com or cloud.xyz.com, it shows only self-signed certs.
6- if i default set for mattermost sub-domain, then in browser it shows me letsencrypt certs. same is with cloud.xyz.com
Now i am looking solution for this.