How to fix error setting SSL with certbot using?

Hello,
I try to set ssl for my php/laravel application under Digital Ocean with Kubuntu 18
as in this articles
https://www.digitalocean.com/community/tutorials/how-to-secure-apache-with-let-s-encrypt-on-ubuntu-18-04

But I got error trying to use certbot to obtain a free SSL certificate :

# sudo ufw status
Status: active

To Action From
-- ------ ----
Apache Full ALLOW Anywhere 
443 ALLOW Anywhere 
80 ALLOW Anywhere 
22/tcp ALLOW Anywhere 
Apache Full (v6) ALLOW Anywhere (v6) 
443 (v6) ALLOW Anywhere (v6) 
80 (v6) ALLOW Anywhere (v6) 
22/tcp (v6) ALLOW Anywhere (v6) 

# sudo certbot --apache -d products-catalog.nilov-sergey-demo-apps.tk -d www.products-catalog.nilov-sergey-demo-apps.tk 
Saving debug log to /var/log/letsencrypt/letsencrypt.log 
Plugins selected: Authenticator apache, Installer apache 
Obtaining a new certificate 
Performing the following challenges:
http-01 challenge for products-catalog.nilov-sergey-demo-apps.tk
http-01 challenge for www.products-catalog.nilov-sergey-demo-apps.tk
Waiting for verification...
Cleaning up challenges
Failed authorization procedure. www.products-catalog.nilov-sergey-demo-apps.tk (http-01): urn:ietf:params:acme:error:dns :: DNS problem: NXDOMAIN looking up A for www.products-catalog.nilov-sergey-demo-apps.tk

IMPORTANT NOTES:
- The following errors were reported by the server:

Domain: www.products-catalog.nilov-sergey-demo-apps.tk
Type: None
Detail: DNS problem: NXDOMAIN looking up A for
www.products-catalog.nilov-sergey-demo-apps.tk

Code (markup):

products-catalog.nilov-sergey-demo-apps.tk - that is my domain I got on freenom.com and seaerch I found a hint that I need to add A-record for www subdomain

I tried to add new record as https://imgur.com/a/ijFxlzN
But trying to sumbit this page I got:

• Error occured: Invalid value in dnsrecord

Code (markup):

IP of my server is 138.68.107.4 and under ssh I enter the console of OS as

ssh root@138.68.107.4

Code (markup):

But in my /etc/hosts file I had next lines pointing to some other hosts on this server:

# 127.0.0.1 localhost
127.0.0.1 localhost.localdomain localhost
138.68.107.4 box.example.com box


# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

138.68.107.4 votes.nilov-sergey-demo-apps.tk
138.68.107.5 products-catalog.nilov-sergey-demo-apps.tk
138.68.107.6 csvp.nilov-sergey-demo-apps.tk
...

Code (markup):

I modified 3 lats lines as :

138.68.107.4 votes.nilov-sergey-demo-apps.tk
138.68.107.4 products-catalog.nilov-sergey-demo-apps.tk
138.68.107.4 csvp.nilov-sergey-demo-apps.tk

Code (markup):

But I still not sure is that is valid value, as I have next error again:

# sudo certbot --apache -d products-catalog.nilov-sergey-demo-apps.tk -d www.products-catalog.nilov-sergey-demo-apps.tk 
Saving debug log to /var/log/letsencrypt/letsencrypt.log 
Plugins selected: Authenticator apache, Installer apache 
Obtaining a new certificate 
Performing the following challenges: 
http-01 challenge for products-catalog.nilov-sergey-demo-apps.tk 
http-01 challenge for www.products-catalog.nilov-sergey-demo-apps.tk 
Waiting for verification... 
Cleaning up challenges 
Failed authorization procedure. www.products-catalog.nilov-sergey-demo-apps.tk (http-01): urn:ietf:params:acme:error:dns :: DNS problem: NXDOMAIN looking up 
A for www.products-catalog.nilov-sergey-demo-apps.tk 
IMPORTANT NOTES: 
- The following errors were reported by the server: 

Domain: www.products-catalog.nilov-sergey-demo-apps.tk 
Type: None 
Detail: DNS problem: NXDOMAIN looking up A for 
www.products-catalog.nilov-sergey-demo-apps.tk

Code (markup):

can reason of this error be in wrong IP in
/etc/hosts or some other issue ?

Thanks!

 

You do not have DNS entry for

www.products-catalog.nilov-sergey-demo-apps.tk

Code (markup):

(note www.). You should either point the www to the server IP or run the certbot command without

-d www. products-catalog.nilov-sergey-demo-apps.tk

Code (markup):