There could be an IP conflict, try rebooting your network; restart modem, router, computer, iPad.
Also, please read this article, it's written for Studio One Remote, but the troubleshooting applies, check out the section for Mac:
http://support.presonus.com/hc/en-us/articles/115000521446-Studio-One-Remote-not-connecting-to-Studio-One-
If still having issues, please submit a support ticket.