I found my answer on the following Presonus Knowledge Base article:
StudioLive RM Mixer - Wired and Wireless Network Setup and Troubleshooting
In order for the mixer to connect to a wireless network, it must be able to see the wireless network. Make sure your router is set to broadcast the wireless network SSID (the wifi network name). If the SSID is hidden, the mixer will not be able to connect to that network, even if it has connected to it previously.
This is quite unfortunate.
As a feature request, might I suggest network configuration capabilities allowing a user to enter the network name for a hidden network, and allowing a device to later reconnect to that network? In today's culture of technical exploitation, prudent security measures dictate hiding the SSID broadcast for wireless networks, especially in public places. A bit more sophistication with regards to this network configuration functionality will be greatly appreciated.