These errors are caused by permissions and something is blocking your connection. Unfortunately this could have various reasons such as;
Your antivirus/Firewall (Check for exceptions/permissions, you may need to add Bannerlord Online to the exceptions and/or whitelisting)
Your network connection settings (Some people bypass this by switching connections like Wifi/Cable/Hotspot.)
Your Modem/Router (Similar to your local firewall, your router can also have security settings to block certain connections/websites)
The earlier suggestion of using a VPN should work for this. But if you can use a Hotspot from your phone, it may work as well.
Because of the various different reasons, it's hard to point out any other good solutions.