Cannot open gitlab with costum domain on my vps

Hi there! I have a ubuntu vps and hope to set a gitlab on it. I have followed this toturial: https://about.gitlab.com/install/#ubuntu and change sudo EXTERNAL_URL="https://gitlab.example.com" apt-get install gitlab-ee
into
EXTERNAL_URL="http://git.chenli.space" apt-get install gitlab-ee
it installed successfully from the terminal:

Upgrade complete! If your GitLab server 
is misbehaving try running              
  sudo gitlab-ctl restart               
before anything else.                   
If you need to roll back to the previous
 version you can use the database      
backup made during the upgrade (scroll u
p for the filename).                    
                                        
W: APT had planned for dpkg to do more t
han it reported back (0 vs 4).          
   Affected packages: gitlab-ee:amd64   

Here is my dns for my domain:

I hope to access gitlab via git.chenli.space

But I cannot open open this webpage.

Then I tried to ping it:

~ >>> ping git.chenli.space                                                                                                                                                     
PING git.chenli.space (173.82.95.97) 56(84) bytes of data.
64 bytes from mail.account-recover.rocks (173.82.95.97): icmp_seq=1 ttl=48 time=195 ms
64 bytes from mail.account-recover.rocks (173.82.95.97): icmp_seq=2 ttl=48 time=207 ms
64 bytes from mail.account-recover.rocks (173.82.95.97): icmp_seq=3 ttl=48 time=214 ms
64 bytes from mail.account-recover.rocks (173.82.95.97): icmp_seq=4 ttl=48 time=204 ms
64 bytes from mail.account-recover.rocks (173.82.95.97): icmp_seq=5 ttl=48 time=211 ms
64 bytes from mail.account-recover.rocks (173.82.95.97): icmp_seq=6 ttl=48 time=202 ms

It seems mail.account-recover.rocks is the problem. But I cannot find the reason.

UPDATE

the page has reponse now:

upgrading ram to 8g solves this problem.

Thanks for sharing the solution!