Gstreamer stuck at setting pipeline to paused

I am currently trying to run gstreamer on ubuntu but there are some errors I face.

When I try to run a simple pipeline, like the video test pipeline

gst-launch-1.0 videotestsrc ! autovideosink

it keeps getting stuck at

Setting pipeline to PAUSED ...

This causes my PC to completely hang there.

When I try another code:

gst-launch-1.0 -vvv udpsrc port=5000 ! application/x-rtp,encoding-name=H265,payload=96 ! rtph265depay ! h265parse ! queue ! avdec_h265 ! autovideosink sync=false async=false> -e

After 15 minutes of waiting, this happens

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Got context from element 'autovideosink0-actual-sink-vaapi': gst.vaapi.Display=context, gst.vaapi.Display=(GstVaapiDisplay)"\(GstVaapiDisplayGLX\)\ vaapidisplayglx1";
Setting pipeline to PLAYING ...
New clock: GstSystemClock

EDIT: I found someone with a similar problem to mine :https://stackoverflow.com/questions/57754353/gst-launch-1-0-videotestsrc-autovideosink-does-not-work-for-me