Web UI Playback "Error loading this resource"

getting this error on all playback in the web UI
major clue is in /var/log/apache2/error.log see below

Bluecherry Version: 2.8.8 server installed on
Ubuntu 18.04.4 LTS (GNU/Linux 4.15.0-88-generic x86_64)

Firefox Nightly 75.0a1 (2020-02-14) (64-bit) on Elementary OS
in browser console:

> NotSupportedError: The media resource indicated by the src attribute or assigned media provider object was not suitable.  

Chrome Version 80.0.3987.132 (Official Build) (64-bit) on Elementary OS
in browser console:

> GET https://25.4.36.228:7001/media/stream-mp4?id=361762 500 (Internal Server Error - MP4 file preparation failed)
> Uncaught (in promise) DOMException: Failed to load because no supported source was found.  

Firefox 73.0.1 (64-bit) on Windows 10
in browser console:

> HTTP load failed with status 500. Load of media resource https://25.4.36.228:7001/media/stream-mp4?id=361790 failed. playback
> NotSupportedError: The media resource indicated by the src attribute or assigned media provider object was not suitable. 

Chrome Version 80.0.3987.132 (Official Build) (64-bit) on Windows 10
in browser console:

> GET https://25.4.36.228:7001/media/stream-mp4?id=360884 500 (Internal Server Error - MP4 file preparation failed)
(anonymous) @ mediaelement-and-player.min.js:27
dispatch @ jquery.min.js:3
r.handle @ jquery.min.js:3
playback:1 Uncaught (in promise) DOMException: Failed to load because no supported source was found. 

Interesting bit is in the server log

tail -f /var/log/apache2/error.log 
    Stream #0:1: Audio: pcm_alaw ([6][0][0][0] / 0x0006), 16000 Hz, 1 channels, 128 kb/s (default)
    Metadata:
      DURATION        : 00:00:20.491000000
Unsupported codec with id 65543 for input stream 1
[Sat Mar 07 09:00:31.056913 2020] [mpm_prefork:notice] [pid 646] AH00169: caught SIGTERM, shutting down
[Sat Mar 07 09:05:02.202416 2020] [mpm_prefork:notice] [pid 11636] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Sat Mar 07 09:05:02.202476 2020] [core:notice] [pid 11636] AH00094: Command line: '/usr/sbin/apache2'
[Sat Mar 07 09:11:01.137919 2020] [mpm_prefork:notice] [pid 11636] AH00169: caught SIGTERM, shutting down
[Sat Mar 07 09:11:42.847152 2020] [mpm_prefork:notice] [pid 632] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1 configured -- resuming normal operations
[Sat Mar 07 09:11:42.847503 2020] [core:notice] [pid 632] AH00094: Command line: '/usr/sbin/apache2'
ffprobe version n3.0 Copyright (c) 2007-2016 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.4.0-1ubuntu1~18.04.1)
  configuration: --prefix=/build/stage --disable-static --enable-shared --cc='ccache gcc -std=c99' --enable-pic --disable-stripping --disable-doc --disable-libxcb --disable-xlib --disable-sdl --disable-everything --enable-indev=v4l2 --enable-protocol=file --enable-protocol=pipe --enable-protocol=http --enable-protocol=https --enable-muxer=matroska --enable-muxer=mjpeg --enable-muxer=rtp --enable-muxer=mp4 --enable-muxer=image2 --enable-muxer=rawvideo --enable-demuxer=rtsp --enable-demuxer=matroska --enable-demuxer=mjpeg --enable-demuxer=rawvideo --enable-demuxer=concat --enable-decoder=h264 --enable-decoder=mpeg4 --enable-decoder=mjpeg --enable-decoder=rawvideo --enable-decoder=aac --enable-decoder=ac3 --enable-decoder=mp2 --enable-decoder=mp3 --enable-decoder=wav --enable-decoder=pcm_f32le --enable-decoder=pcm_f64le --enable-decoder=pcm_s16le --enable-parser=h264 --enable-parser=mpeg4video --enable-parser=mjpeg --enable-encoder=mjpeg --enable-encoder=mpeg4 --enable-encoder=rawvideo --enable-encoder=aac --enable-filter=scale --enable-filter=fps --enable-filter=aresample
  libavutil      55. 17.103 / 55. 17.103
  libavcodec     57. 24.102 / 57. 24.102
  libavformat    57. 25.100 / 57. 25.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 31.100 /  6. 31.100
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
Input #0, matroska,webm, from '/mnt/CCTV_DATA/bluecherry/recordings/2020/03/07/000001/08-03-16.mkv':
  Metadata:
    ENCODER         : Lavf57.25.100
  Duration: 00:00:24.72, start: 0.000000, bitrate: 3560 kb/s
    Stream #0:0: Video: h264 (Main), yuvj420p(pc, bt709), 2560x1440, SAR 1:1 DAR 16:9, 10 fps, 25.08 tbr, 1k tbn, 20 tbc (default)
    Metadata:
      DURATION        : 00:00:24.468000000
    Stream #0:1: Audio: pcm_alaw ([6][0][0][0] / 0x0006), 16000 Hz, 1 channels, 128 kb/s (default)
    Metadata:
      DURATION        : 00:00:24.720000000
Unsupported codec with id 65543 for input stream 1 

Note I turned off Audio recording (unticked Enable audio) and that seems to have ‘fixed’ the playback problem, it was also on camera main stream, the substream was not affected
Dahua Enable IPC-HDW4433C-A
main stream H.264 2560x1414
substream H.264 704x576