• Run as administrator then wait for about 10 seconds to 5 minutes
• use capital `-O` option to change the Mudfish's working method as refer Firewall - Mudfish Master Server
• run `netsh winsock reset` as administrator https://support.microsoft.com/en-us/help/299357/how-to-reset-tcp-ip-by-using-the-netshell-utility
• consider to change MAC Address
• consider reducing MTU from 1450
• run Mudfish with option lowercase `-s` then access to https://ui.mudfish.net:8282
• connect with Mudfish DNS Client If Mudfish DNS Client doesn't work,
• gpedit.msc - Local Computer Policy - Computer Configuration - Administrative Template - Network - DNS Client - Turn off smart multi-homed name resolution - Enabled - OK
• Control Panel\Network and Internet\Network Connections - TAP-Win32 Adapter V9 - Internet Protocol Version 4(TCP/IPv4) Properties - General - Advanced... - IP Settings - Automatic metric - Interface metric - recommended 15
• use capital `-O` option to change the Mudfish's working method as refer Firewall - Mudfish Master Server
• China https://mudfish.net/forums/6/topics/44662 https://mudfish.net/forums/6/topics/37597

I'm so Sorry, I forgot to mention that I am using a Macbook OS X.

1. Open Terminal
2. sudo bash
3. Input Password
4. cd /Applications/Mudfish\ Cloud\ VPN.app/Contents/MacOS/
5. ./Mudfish\ Cloud\ VPN -c -O

or

1. System Preferences...
2. Network
3. Advanced...
4. DNS - Click the + button below DNS Servers to Add a DNS server address then put any DNS Servers to set it manually what you desire https://en.wikipedia.org/wiki/Public_recursive_name_server

Thank you, running it from the terminal with -c -O works.

No longer getting the error. :D