A first check whether the server ip address to ping
Description appear on the map interface is the database server is the network unimpeded.
Second, check your server's firewall is turned off.
Check the firewall is turned off, the reference connection: https://www.cnblogs.com/wangfl/p/11605400.html
If the firewall is turned on, then just turn off the firewall.
Then go Navicat connect to the database. You will be able to succeed.