Some more findings.....
These song files play okay in iTunes on my computer and also with the Apple Music App on my iPhone.
Where they don't play is from JRemote on my iPhone 7 or 14Pro when playing to "this device", in other words on the phone. The files will play when using JRemote but setting the Zone to another player instead of the iPhone device.
I now think the problem is the JRemote player. I assume it has its own player and that's what's used when selecting the Zone as this Device. So, there's something with these AAC files that JRemote does not like. Perhaps I need to submit a help ticket with JRiver. I assume they have something like that.
Here's some version numbers and other info I've collected including song file specs for my copy of Adele, "Hello"
These song files play fine on all other music players in my possession except for JRemote. If there are facts or specs that I'm missing, please let me know. 99% of the time I don't use JRemote to play songs on my iPhone but rather redirect the stream to another Zone and that works great. So, this issue isn't preventing me from using JRemote.
JRemote, version 3.40
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iPhone 14 Pro, iOS 17.0.3
iPhone 7, iOS 15.7.9
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Platinum Notes 10, version 10.0.345.0
Copyright 2007 - 2023, Mixed In Key LLC.
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Media Center, version 31.0.43(64-bit)
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Adele, Hello, ripped with Media Center from CD to ALAC
Info from MediaInfo 23.10, Copyright (c) MediaArea.net SARL)
Format : ALAC
Codec ID : alac
Codec ID/Info : Apple Lossless Audio Codec
Duration : 4 min 55 s
Duration_LastFrame : -50 ms
Bit rate mode : Variable
Bit rate : 807 kb/s
Nominal bit rate : 2 220 Mb/s
Channel(s) : 2 channels
Sampling rate : 44.1 kHz
Bit depth : 16 bits
Stream size : 28.4 MiB (100%)
Encoded date : 2015-12-26 22:26:09 UTC
Tagged date : 2015-12-26 22:26:09 UTC
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AAC converter (qaac64.exe)
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Adele "Hello", AAC conversion
Info from MediaInfo 23.10, Copyright (c) MediaArea.net SARL)
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 4 min 55 s
Duration_LastFrame : -1 ms
Bit rate mode : Variable
Bit rate : 298 kb/s
Maximum bit rate : 320 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 10.5 MiB (99%)
Language : English
Default : Yes
Alternate group : 1