Check the following post if Mac Print App is not working after install:
Check OS X version to ensure correct Mac Print App Version was installed at wēpa website:
- OS X 10.10 Yosemite & Above Users: Download Version 6, the grey ‘Download Latest’ link
- OS X 10.9 Mavericks & Below Users: Download Version 5 – see Java Requirements Post
If incorrect driver installed, uninstall Mac Print App, download correct version and re-install.
If installing Version 5, ensure Java 6 is installed prior to installing, Java Requirements.