To identify a network problem, check the issue using the MTR utility (WinMTR - version for Windows OS) from your computer to the problematic IP on the server.
We also need a check result from the server to your computer (on which you are seeing the problem).
By default, this utility is not installed on the system, so the installation methods on different OSs are listed below.
CentOS:
yum install mtr
Fedora:
dnf install mtr
Debian / Ubuntu:
apt-get install mtr-tiny
Windows:
Using the installer from here - https://sourceforge.net/projects/winmtr/files/latest/download
or from here: http://winmtr.net/download-winmtr/
You need to send at least 100 requests and run in report mode (on Linux), i.e. so that requests are sent and after that the result is displayed on the screen.
It is also necessary to disable name permissions so that IP addresses are displayed instead of their PTR records (-n switch in Linux and disable the Resolve names option in WinMTR).
Example MTR command:
mtr -prnc 100 10.20.30.40
where instead of 10.20.30.40 you need to substitute the problematic IP address.