Unable to connect remotely to mysql (IP address could not be resolved), how to fix?

Question

MySQL

Good afternoon! Trying to connect to mysql on a remote VPS server. Mysql does not start up and throws an error in the log:

[Warning] IP address '5.136.87.201' could not be resolved: Name or service not known

. (before that I connected, did not change anything, the error arose for no apparent reason).
By the way, if you connect to the database locally, everything is fine. Does not start up only from the remote machine.
I found answers on the net only about skip-name-resolve, but this directive only hides the error output to the log, but does not solve the problem. What to do?

Answer 1

This means "the server at the specified IP is unreachable".
Or wrong IP.
Either something is blocking the request or response. For example, iptables, Roskomnadzor, some kind of firewall, etc.

Answer 2

disable iptables on both servers:
/etc/init.d/iptables stop
service iptables stop
and try

Answer 3

In general, this is not a mistake. This is a warning that it was not possible to resolve the address into a name. In such a situation, permissions by name in the muscle will not work.
Where is the error?