Hello, I am new to ubuntu. I need help.

I have created an installation of Wordpress Multisite, I need that the subsites have SSL certificate. My Main site has an Active SSL certificate https://viticlic.com/. When creating the https://demo1.viticlic.com/ subsites, they do not include the SSL certificate. I have looked for information in these corners and I cannot install the SSL.

I followed this [GUIDE]

1. The first time I did not recognize DNS verification.

EXAMPLE

Please deploy a DNS TXT record under the name
_acme-challenge.viticlic.com with the following value:
J50GNXkhGmKCfn-0LQJcknVGtPEAQ_U_WajcLXgqWqo

1. After a few days I tried again and I get this error.

E: Package 'python-virtualenv' has no installation candidate

I already installed Python with this guide but it kept giving me an error.

I hope you can help me.

Beforehand thank you very much.