ffmpeg mp4 video not working on iphone

Question

I have ffmpeg working on my site to let users create various mp4s, and they all work fine on all devices except for one of my conversion functions, which isnt allowing the video to play on my iphone. The same exact video works fine in chrome on my laptop.

This is the code Im using --

// first we merge the audio file with the concat file for images
ffmpeg -i '.$thepath .'/audio.mp3 \
-safe 0 -f concat -i '.$thepath .'/paths.txt \
-af "volume=-1dB" -c:v libx264 -vprofile baseline \
-vf "scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:(ow-iw)/2:(oh-ih)/2" -t 180 -pix_fmt yuv420p -movflags +faststart -y '.$output.' 2>&1

// now add background music
ffmpeg \
-i '.$output.' -i '.$musicpath .'/'.$music.'.mp3 \
-filter_complex "[1:a]volume=-25dB,apad[A];[0:a][A]amerge[out]" \
-c:v copy -map 0:v -map [out] -vprofile baseline -level 3.0 \
-pix_fmt yuv420p -movflags +faststart -shortest \
-y '.$thepath.'/output-'.$v_Id.'.mp4 2>&1

Because this is happening on iphone and I don't have a Mac, I am unable to see the output. Running the same code on my laptop though, I get this output ---

ffmpeg version N-90767-g768c077-syslint Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-16)
  configuration: --prefix=/usr/local/cpffmpeg --enable-shared --enable-nonfree --enable-gpl --enable-pthreads --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --extra-cflags=-I/usr/local/cpffmpeg/include --extra-ldflags=-L/usr/local/cpffmpeg/lib --enable-version3 --extra-version=syslint
  libavutil      56. 15.100 / 56. 15.100
  libavcodec     58. 19.100 / 58. 19.100
  libavformat    58. 13.100 / 58. 13.100
  libavdevice    58.  4.100 / 58.  4.100
  libavfilter     7. 18.100 /  7. 18.100
  libswscale      5.  2.100 /  5.  2.100
  libswresample   3.  2.100 /  3.  2.100
  libpostproc    55.  2.100 / 55.  2.100
[mp3 @ 0x12c1900] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from '/path/to/audio.mp3':
  Metadata:
    encoder         : Lavf57.71.100
  Duration: 00:00:18.00, start: 0.000000, bitrate: 48 kb/s
    Stream #0:0: Audio: mp3, 22050 Hz, mono, fltp, 48 kb/s
Input #1, concat, from '/path/to/paths.txt':
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #1:0: Video: png, rgb24(pc), 754x424, 25 tbr, 25 tbn, 25 tbc
Stream mapping:
  Stream #1:0 -> #0:0 (png (native) -> h264 (libx264))
  Stream #0:0 -> #0:1 (mp3 (mp3float) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 0x12eb740] using cpu capabilities: none!
[libx264 @ 0x12eb740] profile Constrained Baseline, level 3.1
[libx264 @ 0x12eb740] 264 - core 155 r2901 7d0ff22 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=0 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=22 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to '/path/to/output-4672-first.mp4':
  Metadata:
    encoder         : Lavf58.13.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 1280x720, q=-1--1, 25 fps, 12800 tbn, 25 tbc
    Metadata:
      encoder         : Lavc58.19.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 22050 Hz, mono, fltp, 69 kb/s
    Metadata:
      encoder         : Lavc58.19.100 aac
[swscaler @ 0x13ddb00] Warning: data is not aligned! This can lead to a speed loss
frame=  151 fps= 47 q=28.0 size=       0kB time=00:00:03.48 bitrate=   0.1kbits/s dup=149 drop=0 speed=1.08x    
frame=  301 fps= 50 q=28.0 size=       0kB time=00:00:09.48 bitrate=   0.0kbits/s dup=298 drop=0 speed=1.58x    
frame=  451 fps= 54 q=28.0 size=     256kB time=00:00:15.48 bitrate= 135.5kbits/s dup=447 drop=0 speed=1.87x    
frame=  599 fps= 58 q=28.0 size=     512kB time=00:00:21.40 bitrate= 196.0kbits/s dup=595 drop=0 speed=2.06x    
[mp4 @ 0x12ea0c0] Starting second pass: moving the moov atom to the beginning of the file
frame=  599 fps= 54 q=-1.0 Lsize=     619kB time=00:00:23.92 bitrate= 212.0kbits/s dup=743 drop=0 speed=2.16x    
video:434kB audio:175kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.592660%
[libx264 @ 0x12eb740] frame I:4     Avg QP:13.86  size: 99376
[libx264 @ 0x12eb740] frame P:595   Avg QP:14.17  size:    78
[libx264 @ 0x12eb740] mb I  I16..4: 43.0%  0.0% 57.0%
[libx264 @ 0x12eb740] mb P  I16..4:  0.0%  0.0%  0.0%  P16..4:  0.5%  0.1%  0.0%  0.0%  0.0%    skip:99.5%
[libx264 @ 0x12eb740] coded y,uvDC,uvAC intra: 57.5% 55.0% 48.9% inter: 0.0% 0.4% 0.0%
[libx264 @ 0x12eb740] i16 v,h,dc,p: 74% 11%  4% 11%
[libx264 @ 0x12eb740] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 28% 30% 12%  4%  5%  4%  7%  4%  7%
[libx264 @ 0x12eb740] i8c dc,h,v,p: 56% 21% 17%  5%
[libx264 @ 0x12eb740] ref P L0: 95.5%  2.6%  1.9%
[libx264 @ 0x12eb740] kb/s:148.30
[aac @ 0x12ecac0] Qavg: 9185.104

ffmpeg version N-90767-g768c077-syslint Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-16)
  configuration: --prefix=/usr/local/cpffmpeg --enable-shared --enable-nonfree --enable-gpl --enable-pthreads --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --extra-cflags=-I/usr/local/cpffmpeg/include --extra-ldflags=-L/usr/local/cpffmpeg/lib --enable-version3 --extra-version=syslint
  libavutil      56. 15.100 / 56. 15.100
  libavcodec     58. 19.100 / 58. 19.100
  libavformat    58. 13.100 / 58. 13.100
  libavdevice    58.  4.100 / 58.  4.100
  libavfilter     7. 18.100 /  7. 18.100
  libswscale      5.  2.100 /  5.  2.100
  libswresample   3.  2.100 /  3.  2.100
  libpostproc    55.  2.100 / 55.  2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/path/to/output-4672-first.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.13.100
  Duration: 00:00:23.96, start: 0.000000, bitrate: 211 kb/s
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1280x720, 148 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 22050 Hz, mono, fltp, 79 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #1, mp3, from '/path/to/creative_minds.mp3':
  Duration: 00:02:27.23, start: 0.025057, bitrate: 160 kb/s
    Stream #1:0: Audio: mp3, 44100 Hz, stereo, fltp, 160 kb/s
    Metadata:
      encoder         : LAME3.97 
    Side data:
      replaygain: track gain - -8.100000, track peak - unknown, album gain - unknown, album peak - unknown, 
Stream mapping:
  Stream #0:1 (aac) -> amerge:in0
  Stream #1:0 (mp3float) -> volume
  Stream #0:0 -> #0:0 (copy)
  amerge -> Stream #0:1 (aac)
Press [q] to stop, [?] for help
[Parsed_amerge_2 @ 0x95f580] No channel layout for input 1
Output #0, mp4, to '/path/to/output-4672.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.13.100
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1280x720, q=2-31, 148 kb/s, 25 fps, 25 tbr, 12800 tbn, 12800 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 22050 Hz, 3.0, fltp, 197 kb/s (default)
    Metadata:
      encoder         : Lavc58.19.100 aac
frame=  439 fps=0.0 q=-1.0 size=     768kB time=00:00:17.52 bitrate= 359.1kbits/s speed=  35x    
[mp4 @ 0x78dc80] Starting second pass: moving the moov atom to the beginning of the file
frame=  599 fps=0.0 q=-1.0 Lsize=     889kB time=00:00:23.92 bitrate= 304.6kbits/s speed=46.5x    
video:434kB audio:445kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.096470%