Phone Not Showing On Device List

[norrisworldwide]

I have an iPhone 6 and want to play music wirelessly to my speakers. I have an old iPhone 5 plugged into the speakers. Both phones on the same network. Both devices logged into the same (Premium trial) Spotify account. I can play music from the iPhone 5 and control the iPhone 5. IF music is playing, it shows up on my device list on my iPhone 6. However, if I switch to play music on my iPhone 6, my iPhone 5 is no longer visible in my device list. What's going on?

[norrisworldwide]

So, I tried another device. This time an iPhone 4. From the iPhone 4, I see my iPhone 6 in my list of devices. However, from my iPhone 6, I do not see my iPhone 4 in my list of devices, unless it's already playing music. The same problem as before. What is going on!?! Please help!!!

[norrisworldwide]

So I just tested on my wifes iPhone 6. Downloaded newest version of app. Logged into same account. Same wifi network. I see no other devices on the list, despite there before an iPhone 6, Macbook and iPhone 4 all with Spotify open.