You're able to see the traffic on your Mac machine but iOS or android devices couldn't access to the Internet after changing the Proxy Config in Wifi Setting.
Couldn't access to Proxyman local server http://proxy.man.ssl for installing the Proxyman Certificate
Please make sure to double-check the following steps:
If they're on different network, they are unable to connect to each other.
For iOS Devices: Navigate to Setting -> General -> VPN and make sure the VPN status is OFF
For macOS: Quit all VPN app if needed
On macOS: Navigate to System Preference -> Security & Privacy -> Firewall tab -> Option
Block All incoming connections is OFF
Proxyman app is allowed incoming connection
If there is no Proxyman app, please add Proxyman app by clicking on + button
Automatically allow built-in software to receive incoming connection is ON
Automatically allow downloaded signed software to receive incoming connections is ON
Some companies blocks all open port by default. Therefore, your iOS devices couldn't access to Proxyman's port.
If you follow all above steps and all configuration are correct but it hasn't resolved your cases yet.
Please try to ON/OFF your Wifi, Forget the Wifi Network (iOS) and Restart the Computer.