fails to pull images from containers.intersystems.com

What is the point of having a dedicated registry if it does not work properly most of the time?

$ docker pull containers.intersystems.com/intersystems/iris-community:latest-em
latest-em: Pulling from intersystems/iris-community
5526e9f3d5c5: Already exists
352b407541ae: Already exists
f6bff04f5338: Already exists
8c3b528467ff: Downloading [=======================>                           ]  125.8MB/262.2MB
e2b23b0bff05: Downloading [=============>                                     ]  124.8MB/462.1MB
failed to copy: httpReadSeeker: failed open: could not fetch content descriptor sha256:8c3b528467ff8cc07d86a4979e3e7b8fd36734205539923c8750e1d523f23367 (application/vnd.docker.image.rootfs.diff.tar.gzip) from remote: not found

Exactly the same image fortunately available on Docker hub, but it's working fine there

$ docker pull intersystems/iris-community:latest-em                                                                      latest-em: Pulling from intersystems/iris-community
5526e9f3d5c5: Already exists
e2b23b0bff05: Download complete
352b407541ae: Already exists
f6bff04f5338: Already exists
8c3b528467ff: Download complete
Digest: sha256:1d40078679d37a642654c3e490d0a095a937a1b11ff75164207d057c6cf58b68
Status: Downloaded newer image for intersystems/iris-community:latest-em
docker.io/intersystems/iris-community:latest-em

Hashes of the layers are exactly the same, the same image, so where is the issue?