Docker xvfb-run killed with ffmpeg - node.js

Question

error:
xvfb-run: line 169: 18 Killed DISPLAY=:$SERVERNUM XAUTHORITY=$AUTHFILE
Dockerfile xvfb command
ENTRYPOINT ["/usr/bin/dumb-init", "--", "xvfb-run", "--server-args", "-screen 0 1280x1024x24 -ac"]
Full Dockerfile
FROM ubuntu:focal-20220302
WORKDIR /app
# Ensures tzinfo doesn't ask for region info.
ENV DEBIAN_FRONTEND noninteractive
RUN apt-get update && apt-get install -y \
dumb-init \
xvfb \
build-essential libxi-dev libglu1-mesa-dev libglew-dev pkg-config
# Source: https://gist.github.com/remarkablemark/aacf14c29b3f01d6900d13137b21db3a
# replace shell with bash so we can source files
RUN rm /bin/sh && ln -s /bin/bash /bin/sh
# update the repository sources list
# and install dependencies
RUN apt-get update \
&& apt-get install -y curl \
&& apt-get -y autoclean
RUN curl -fsSL https://deb.nodesource.com/setup_14.x | bash -
RUN apt-get install -y nodejs
# confirm installation
RUN node -v
RUN npm -v
# FONT CONFIG
RUN apt-get install fontconfig -y
## INSTALL EDITLY
# ## Install app dependencies
COPY package.json /app/
RUN npm install
# Add app source
COPY . /app
# Ensure `editly` binary available in container
RUN npm link
RUN apt-get update && apt-get install -y wget \
xz-utils \
dumb-init \
xvfb
# Get ffmpeg and ffprobe with static build
RUN wget https://johnvansickle.com/ffmpeg/releases/ffmpeg-release-amd64-static.tar.xz \
&& tar xvf ffmpeg-release-amd64-static.tar.xz \
&& cp ffmpeg-5.0-amd64-static/ffmpeg /usr/local/bin/ \
&& cp ffmpeg-5.0-amd64-static/ffprobe /usr/local/bin/ \
&& rm -rf ffmpeg-release-amd64-static.tar.xz \
&& rm -rf ffmpeg-5.0-amd64-static
# Ensure ffmpeg and ffprobe are successfully copied
RUN ffmpeg -version && ffprobe -version
ENTRYPOINT ["/usr/bin/dumb-init", "--", "xvfb-run", "--server-args", "-screen 0 1280x1024x24 -ac"]
EXPOSE 3000
CMD [ "node","./index.js" ]