I had the same problem - and have fixed it by trial and error.
When you get the DMG from the Epson/SN site and open it you get the screen which shows 'double click' on 'Install Navi' (which should start the installer) . For me the installer appeared to open but then took hours and didnt actually complete.
TO FIX
Rather than 'double clicking' on 'Install NAVI' if you click on bottom right of the window and stretch it you will see four folders appear; Driver, Apps, Network and Manual.
1. Click on Driver > which shows sub folders Printer and Scanner. Click on each in turn and then click on the content files: EPSON Printer.PKG and EPSON Scanner2.PKG. This will launch the installers - follow the steps on screen to install.
2. Repeat with Apps> Download Navigate>Epson Software update. When you run through this it will check whether there is later version. You only need to do that once - it just keeps offering you to check again.
3. Repeat with Network> EpsonNet Setup and it will take you through the wifi etc setup.
You have now manually unpackaged the install files and carried out the installation which was not working automatically.
Hope this helps 🙂