LetsEncrypt SSL for hostname

[cupcode]

Hello. I'm a beginner in DirectAdmin. After installing it on my VPS and turning Let'sEncrypt on using this tutorial, I managed to enable it for hostname too with this tutorial.
After that when I try to login to DA using server IP or hostname (which again redirects to IP), I face this error in Firefox:

and after deciding to revoke the SSL for hostname, I face this error :

Why this happens?
What should I do to avoid these errors when I try to access DA panel using server IP address?

 

[mentik_yusmantara]

It should this tutorial

https://help.directadmin.com/item.php?id=15

 

[cupcode]

Thanks to @kadek_mentik, "Ability to force which hostname is used when accessing DA" worked for me.