Mac's and networks are always special.
You need to configure the IP address in the IMatch Anywhere WebViewer config file so the Web Viewer knows where to find the server running IMatch Anywhere:
"imwsUrl": "http://YOUR-PC-NAME:PORT/",During the installation, the installer configures this entry to match the machine name of the computer on which you install IMWS.
This works out-of-the-box,
unless you are using Apple devices which still don't support standard name resolution (PC name => IP address) conventions.
Open the config file with a text editor and change the imwsUrl to use the IP address instead of YOUR-PC-NAME.
For details, open the IMWS documentation by clicking the Help button in the controller (or pressing F1).
Then click on
WebViewer Configuration. This explains where to find the configuration file and how to change it.