Why can't I get ocaml/opam:ubuntu-16.04_ocaml-4.03.0 docker Image?

I was trying to run:

docker build -f hol-light/Dockerfile_check_proofs --ulimit stack=1000000000 --tag check_proofs hol-light/

but I get the error:

Sending build context to Docker daemon   48.9MB
Step 1/16 : FROM ocaml/opam:ubuntu-16.04_ocaml-4.03.0
pull access denied for ocaml/opam, repository does not exist or may require 'docker login': denied: requested access to the resource is denied


The docker file is: https://github.com/brain-research/hol-light/blob/master/Dockerfile_check_proofs

FROM ocaml/opam:ubuntu-16.04_ocaml-4.03.0
WORKDIR /home/opam/
SHELL ["/bin/bash", "-c"]
ENV PATH="/home/opam/.opam/4.03.0/bin:${PATH}"

### Install num
RUN opam install num

### Install campl5
RUN git clone --depth 1 -b rel617 https://github.com/camlp5/camlp5
RUN cd camlp5 &&\
  ./configure &&\
  make world.opt &&\
  make install &&\
  # meta/Makefile in camlp5 skips these files which we need, so copy them
  # manually.
  cp {main/pcaml,main/quotation,etc/pa_reloc,meta/q_MLast}.{cmi,cmx,o} `camlp5 -where`

### Install grpc
RUN sudo apt-get update &&\
  sudo apt-get install -y build-essential autoconf libtool pkg-config clang libc++-dev
RUN git clone -b 'v1.17.1' --recurse-submodule --depth 1 https://github.com/grpc/grpc
RUN sudo make -C grpc install-headers_c install-static_c install-pkg-config_c\
    install-headers_cxx install-static_cxx install-pkg-config_cxx\
RUN sudo make -C grpc/third_party/protobuf install

### Install farmhash
RUN git clone --depth 1 https://github.com/google/farmhash &&\
  cd farmhash &&\
RUN sudo make -C farmhash install

### Build binaries
COPY --chown=opam:0 . src/
RUN make -C src check_proofs
CMD ["./src/check_proofs"]


The error is most likely caused by the non-existence of the tag ubuntu-16.04_ocaml-4.03.0. To find a list of available tags (and therefore, images to build from), you can visit https://hub.docker.com/r/ocaml/opam/tags. Or, you could try a simple pull of the image you’re requesting to see if it exists or is in a public repository.

My research (a quick check) suggests that image tag does not exist. So, you’ll probably need to use a different tag, i.e. image that’s been built based on ubuntu 16.04 and a different version of ocaml/opam.

which one do I need to use as a repalcement?

The ocaml/opam repository has been deprecated for over 2 years now as opam 1.x is EOL, and the replacement is the ocaml/opam2 repository. Try just switching the FROM to ocaml/opam2:4.03 and see howh the build goes.