When receiving the error it could be that your IP address is on a blacklist or its not allowed to connect to server due to firewall restrictions.
Firstly, confirm your IP address at https://www.whatismyip.com/
You can verify whether the IP address is blacklisted by having it checked through websites such as MXToolbox.
https://mxtoolbox.com/blacklists.aspx
The other alternative is that the IP is outside of South Africa or you're using a VPN and would be monitored more strictly.
Now check the IP country by looking at iplocation.net
If using a VPN try using a VPN Provider that has ZA servers (nodes) like IPVanish or ExpressVPN.
