@trauts14 ,

From your description, it should be EAP225-Outdoor. When you put it in the secondary WLAN, it doesn't broadcast the SSID. Here are some suggestions for you to have a try.
1. Please check the physical connection of the AP. The LED of the AP is green? If not, then we can know that the AP is not working.
2. Please check the DHCP Server. In the DHCP server, can you see the AP? Does the AP get a normal IP address? You can try to ping the IP of the AP in other clients. 
3. Actually, if you want your guests to use the portal, you can directly put the AP in the primary WLAN, then just set another guest SSID for the guests. 
Hope this is useful for you!

How do I establish a 2nd SSID?

@trauts14 

It will be very easy to create another SSID. For the Omada Controller, we can 8 SSIDs in 2.4G and 8 SSIDs in 5G. Please see the attached photo.