SSL certificate problem, verify that the CA cert is OK: Is this a client problem?

Question

Digital certificates

I contact the server via https and get the following response:

curl: (60) SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
More details here: curl.haxx.se/docs/sslcerts.html

curl performs SSL certificate verification by default, using a "bundle"
of Certificate Authority (CA) public keys (CA certs). If the default
bundle file isn't adequate, you can specify an alternate file
using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in
the bundle, the certificate verification probably failed due to a
problem with the certificate (it might be expired, or the name might
not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use
the -k (or --insecure) option.

Googling, I really could not understand whether this is a client or server problem. Requests to other servers via https do not produce such an error.

As a server administrator how can I solve this error?

Answer 1

Check the domain somewhere on checkers like https://www.sslchecker.com/sslchecker and https://www.ssllabs.com/ssltest/

Answer 2

I had the same problem, I want to say right away - check your antivirus software, because my Kasspersky blocked me ssl2 :D