Why is a certificate issued from another domain?

Question

Domain Name System

Good afternoon.
A strange error came out that when entering the site, a certificate from another domain is issued (seen in the video ).
As you can see, the transition is on one site, and the certificate is from another.
In this case, both sites are on the same server under isp.
This is the first such case, so we cannot initiate this error.
Tell me how to be.
P.S. If someone has an iphone, check the transition through the site (optional :)).

Answer 1

check the correspondence of ip addresses in dns and web server configuration.