Radio streams unplayable by some but not all Reciva radios

[Zeewier]

I have four Reciva based internet radios and I find that the two older ones are unable to play radio streams served via UPnP by MinimServer/MininStreamer.

The test streams that I have been trying to play are included in the .m3u playlist which looks as follows:

#EXTM3U
#EXTINF:-1,[*NPO_R1;mp3] NPO Radio 1
http://icecast.omroep.nl/radio1-sb-mp3.m3u
#EXTINF:-1,[*NPO_N24;mp3] NPO Nieuws 24
http://icecast.omroep.nl/nieuws24-sb-mp3.m3u
#EXTINF:-1,[*NPO_R4] NPO Radio 4
http://icecast.omroep.nl/radio4-bb-mp3.m3u

The relatively new radio Avox TMA1 plays these streams without a problem but the slightly older Avox Petite detects the playlist and the streams but remains stuck on "connecting".
I had noticed exactly the same problem with the new BBC HLS AAC streams which only the two newer radios can play if stream.transcode is set to aac:L16. The stream converter is ffmpeg. The newer radios are on a different (more recent) firmware version that the other two.

It would be great if my two older radios also could play radio streams served by MinimStreamer, maybe by activating the correct properties. Debug logs showing connection attempts by the Avox TMA1 (successful) and the Avox Petite (unsuccessful) are attached.