Unable to trans size video

Hello devs,

Please I am having a challenge trying to reduce the size of a video.

I am using the command below

 gst-launch-1.0.exe filesrc location=/path/to/mp4 ! qtdemux name=d
d.video_0 ! h264parse ! avdec_h264 ! videoconvert ! videoscale !
video/x-raw,width=1280,height=720,framerate=15/1 ! autovideosink

But I am getting the following error:

../gst-plugins-good-1.22.6/gst/isomp4/qtdemux.c(6976): gst_qtdemux_loop ():
/GstPipeline:pipeline0/GstQTDemux:d:
streaming stopped, reason not-linked (-1)
WARNING: from element /GstPipeline:pipeline0/GstQTDemux:d: Delayed linking
failed.
ERROR: pipeline doesn't want to preroll.
Additional debug info:
gst/parse/grammar.y(855): gst_parse_no_more_pads ():
/GstPipeline:pipeline0/GstQTDemux:d:
failed delayed linking pad  video_0 of GstQTDemux named d to some pad of
GstH264Parse named h264parse0
Setting pipeline to NULL ...
Freeing pipeline ...

A quick note:
If I remove the videoconvert, videoscale & caps-filter from the pipeline it
works.

I am just struggling to understand why the demux element cannot link to the
next element when they are caps compatible. I know I am missing out on
something but I can't seem to figure it out.

Thanks.

Kind regards.