# TLJH service stalling on login

**URL:** <https://discourse.jupyter.org/t/tljh-service-stalling-on-login/38813>\
**Category:** The Littlest JupyterHub\
**Created:** [July 29, 2026, 9:29pm UTC](https://discourse.jupyter.org/t/tljh-service-stalling-on-login/38813 "2026-07-29T21:29:41Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![wjcapehart](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/wjcapehart/32/6947_2.png) [@wjcapehart](https://discourse.jupyter.org/u/wjcapehart)\
**Post date:** [July 29, 2026, 9:29pm UTC](https://discourse.jupyter.org/t/tljh-service-stalling-on-login/38813/1 "2026-07-29T21:29:41Z")

</div>

Hello all: Our TLJH service over the past few days has been stalling on login for me (the admin [but definitely not a sysadmin!]) and our students. This is on a service running Ubuntu 24.04.4 LTS.

I have rebooted the server, restarted the machine, and completely wiped the TLJH installation, but the problem persists consistently with the same error.

My logs for traefik, jupyterhub and an example of my hung session are linked here as githib gists. (I’ve swapped out myservername, my username, and the client’s IP address with capitalized labels).

Guidance would be appreciated.

> <https://gist.github.com/wjcapehart/26d0aaf069f5c08fe4c5d202a2717917>
>
> There are more than three files. show original

List of packages from recent complete reinstall of TLJH:

```auto
mamba list
List of packages in environment: "/opt/tljh/user"

  Name Version Build Channel    
────────────────────────────────────────────────────────────────────────────
  Mako 1.3.12 pypi_0 pypi       
  PyYAML 6.0.3 pypi_0 pypi       
  Pygments 2.20.0 pypi_0 pypi       
  SQLAlchemy 2.0.51 pypi_0 pypi       
  Send2Trash 2.1.0 pypi_0 pypi       
  _libgcc_mutex 0.1 conda_forge conda-forge
  _openmp_mutex 4.5 2_gnu conda-forge
  _python_abi3_support 1.0 hd8ed1ab_3 conda-forge
  alembic 1.18.5 pypi_0 pypi       
  annotated-types 0.8.0 pyhd8ed1ab_0 conda-forge
  anyio 4.14.2 pyhcf101f3_0 conda-forge
  archspec 0.2.3 pyhd8ed1ab_0 conda-forge
  argon2-cffi 25.1.0 pypi_0 pypi       
  argon2-cffi-bindings 25.1.0 pypi_0 pypi       
  arrow 1.4.0 pypi_0 pypi       
  asttokens 3.0.2 pypi_0 pypi       
  async-lru 2.3.0 pypi_0 pypi       
  attrs 26.1.0 pypi_0 pypi       
  babel 2.18.0 pypi_0 pypi       
  backports.zstd 1.6.0 py312h90b7ffd_0 conda-forge
  beautifulsoup4 4.15.0 pypi_0 pypi       
  bleach 6.4.0 pypi_0 pypi       
  boltons 24.0.0 pyhd8ed1ab_0 conda-forge
  brotli-python 1.1.0 py312h2ec8cdc_2 conda-forge
  bzip2 1.0.8 h4bc722e_7 conda-forge
  c-ares 1.34.8 hb03c661_0 conda-forge
  ca-certificates 2026.7.22 hbd8a1cb_0 conda-forge
  cached-property 1.5.2 hd8ed1ab_2 conda-forge
  cached_property 1.5.2 pyha770c72_2 conda-forge
  certifi 2026.7.22 pyhd8ed1ab_0 conda-forge
  certipy 0.2.3 pypi_0 pypi       
  cffi 2.1.0 pypi_0 pypi       
  charset-normalizer 3.3.2 pyhd8ed1ab_0 conda-forge
  colorama 0.4.6 pyhd8ed1ab_0 conda-forge
  comm 0.2.3 pypi_0 pypi       
  conda 26.5.3 py312h20c3967_2 conda-forge
  conda-index 0.12.1 pyhd8ed1ab_0 conda-forge
  conda-libmamba-solver 26.7.0 pyhcf101f3_0 conda-forge
  conda-lockfiles 0.2.1 pyhd8ed1ab_0 conda-forge
  conda-package-handling 2.3.0 pyh7900ff3_0 conda-forge
  conda-package-streaming 0.13.0 pyhd8ed1ab_0 conda-forge
  conda-pypi 0.11.0 py312h20c3967_1 conda-forge
  conda-rattler-solver 0.1.1 pyhcf101f3_0 conda-forge
  conda-self 0.2.1 pyhd8ed1ab_0 conda-forge
  cpp-expected 1.3.1 h171cf75_0 conda-forge
  cpython 3.12.13 py312hd8ed1ab_0 conda-forge
  cryptography 49.0.0 pypi_0 pypi       
  debugpy 1.8.21 pypi_0 pypi       
  decorator 5.3.1 pypi_0 pypi       
  defusedxml 0.7.1 pypi_0 pypi       
  distro 1.9.0 pyhd8ed1ab_0 conda-forge
  exceptiongroup 1.3.1 pyhd8ed1ab_0 conda-forge
  executing 2.2.1 pypi_0 pypi       
  fastjsonschema 2.22.1 pypi_0 pypi       
  filelock 3.32.0 pyhd8ed1ab_0 conda-forge
  fmt 12.1.0 hff5e90c_0 conda-forge
  fqdn 1.5.1 pypi_0 pypi       
  frozendict 2.4.4 py312h66e93f0_1 conda-forge
  greenlet 3.5.4 pypi_0 pypi       
  h11 0.16.0 pyhcf101f3_1 conda-forge
  h2 4.1.0 pyhd8ed1ab_0 conda-forge
  hpack 4.0.0 pyh9f0ad1d_0 conda-forge
  httpcore 1.0.9 pyh29332c3_0 conda-forge
  httpx 0.28.1 pyhd8ed1ab_0 conda-forge
  hyperframe 6.0.1 pyhd8ed1ab_0 conda-forge
  icu 75.1 he02047a_0 conda-forge
  idna 3.10 pyhd8ed1ab_0 conda-forge
  importlib-metadata 9.0.0 pyhcf101f3_0 conda-forge
  ipykernel 7.3.0 pypi_0 pypi       
  ipython 9.15.0 pypi_0 pypi       
  ipython_pygments_lexers 1.1.1 pypi_0 pypi       
  ipywidgets 8.1.8 pypi_0 pypi       
  isoduration 20.11.0 pypi_0 pypi       
  jedi 0.20.0 pypi_0 pypi       
  jinja2 3.1.6 pyhcf101f3_1 conda-forge
  json5 0.15.0 pypi_0 pypi       
  jsonpatch 1.33 pyhd8ed1ab_0 conda-forge
  jsonpointer 3.0.0 py312h7900ff3_1 conda-forge
  jsonschema 4.26.0 pypi_0 pypi       
  jsonschema-specifications 2025.9.1 pypi_0 pypi       
  jupyter-events 0.12.1 pypi_0 pypi       
  jupyter-lsp 2.3.1 pypi_0 pypi       
  jupyter-resource-usage 1.2.1 pypi_0 pypi       
  jupyter_builder 1.1.1 pypi_0 pypi       
  jupyter_client 8.9.1 pypi_0 pypi       
  jupyter_core 5.9.1 pypi_0 pypi       
  jupyter_server 2.20.0 pypi_0 pypi       
  jupyter_server_terminals 0.5.4 pypi_0 pypi       
  jupyterhub 5.5.0 pypi_0 pypi       
  jupyterlab 4.6.2 pypi_0 pypi       
  jupyterlab_pygments 0.3.0 pypi_0 pypi       
  jupyterlab_server 2.28.0 pypi_0 pypi       
  jupyterlab_widgets 3.0.16 pypi_0 pypi       
  keyutils 1.6.3 hb9d3cd8_0 conda-forge
  krb5 1.22.2 hbde042b_1 conda-forge
  lark 1.3.1 pypi_0 pypi       
  ld_impl_linux-64 2.40 hf3520f5_7 conda-forge
  libarchive 3.8.9 gpl_hc2c16d8_100 conda-forge
  libcurl 8.21.0 hcf29cc6_1 conda-forge
  libedit 3.1.20250104 pl5321h7949ede_0 conda-forge
  libev 4.33 hd590300_2 conda-forge
  libexpat 2.6.3 h5888daf_0 conda-forge
  libffi 3.4.2 h7f98852_5 conda-forge
  libgcc 14.1.0 h77fa898_1 conda-forge
  libgcc-ng 14.1.0 h69a702a_1 conda-forge
  libgomp 14.1.0 h77fa898_1 conda-forge
  libiconv 1.18 h3b78370_2 conda-forge
  liblzma 5.8.3 hb03c661_0 conda-forge
  liblzma-devel 5.8.3 hb03c661_0 conda-forge
  libmamba 2.8.1 hd28c85e_0 conda-forge
  libmamba-spdlog 2.8.1 h9b73f26_0 conda-forge
  libmambapy 2.8.1 py312h392716c_0 conda-forge
  libmsgpack-c 6.1.0 h54a6638_6 conda-forge
  libnghttp2 1.68.1 h877daf1_0 conda-forge
  libnsl 2.0.1 hd590300_0 conda-forge
  libsolv 0.7.39 h9463b59_0 conda-forge
  libsqlite 3.46.1 hadc24fc_0 conda-forge
  libssh2 1.11.1 hcf80075_0 conda-forge
  libstdcxx 14.1.0 hc0a3c3a_1 conda-forge
  libstdcxx-ng 14.1.0 h4852527_1 conda-forge
  libuuid 2.38.1 h0b41bf4_0 conda-forge
  libxcrypt 4.4.36 hd590300_1 conda-forge
  libxml2 2.15.1 h26afc86_0 conda-forge
  libxml2-16 2.15.1 ha9997c6_0 conda-forge
  libzlib 1.3.2 h25fd6f3_2 conda-forge
  lz4-c 1.10.0 h5888daf_1 conda-forge
  lzo 2.10 hd590300_1001 conda-forge
  mamba 2.8.1 h73a5c8a_0 conda-forge
  markupsafe 3.0.3 py312h8a5da7c_1 conda-forge
  matplotlib-inline 0.2.2 pypi_0 pypi       
  menuinst 2.1.2 py312h7900ff3_1 conda-forge
  mistune 3.3.4 pypi_0 pypi       
  msgpack-python 1.2.1 py312h0a2e395_1 conda-forge
  nbclient 0.11.0 pypi_0 pypi       
  nbconvert 7.17.1 pypi_0 pypi       
  nbformat 5.10.4 pypi_0 pypi       
  nbgitpuller 1.3.0 pypi_0 pypi       
  ncurses 6.5 he02047a_1 conda-forge
  nest-asyncio2 1.7.2 pypi_0 pypi       
  nlohmann_json-abi 3.12.0 h0f90c79_1 conda-forge
  notebook 7.6.1 pypi_0 pypi       
  notebook_shim 0.2.4 pypi_0 pypi       
  oauthlib 3.3.1 pypi_0 pypi       
  openssl 3.6.3 h35e630c_0 conda-forge
  packaging 24.1 pyhd8ed1ab_0 conda-forge
  pamela 1.2.0 pypi_0 pypi       
  pandocfilters 1.5.1 pypi_0 pypi       
  parso 0.8.7 pypi_0 pypi       
  pexpect 4.9.0 pypi_0 pypi       
  pip 24.2 pyh8b19718_1 conda-forge
  platformdirs 4.3.6 pyhd8ed1ab_0 conda-forge
  pluggy 1.6.0 pyhf9edf01_1 conda-forge
  prometheus_client 0.26.0 pypi_0 pypi       
  prompt_toolkit 3.0.53 pypi_0 pypi       
  psutil 7.2.2 pypi_0 pypi       
  ptyprocess 0.7.0 pypi_0 pypi       
  pure_eval 0.2.3 pypi_0 pypi       
  py-rattler 0.25.0 py310h70157a2_2 conda-forge
  pybind11-abi 4 hd8ed1ab_3 conda-forge
  pycosat 0.6.6 py312h98912ed_0 conda-forge
  pycparser 2.22 pyhd8ed1ab_0 conda-forge
  pycurl 7.47.0 py312hcf3dbcf_0 conda-forge
  pydantic 2.13.4 pyhcf101f3_0 conda-forge
  pydantic-core 2.46.4 py312h868fb18_0 conda-forge
  pyproject_hooks 1.2.0 pyhd8ed1ab_1 conda-forge
  pysocks 1.7.1 pyha2e5f31_6 conda-forge
  python 3.12.6 hc5c86c4_1_cpython conda-forge
  python-build 1.5.0 pyhc364b38_0 conda-forge
  python-dateutil 2.9.0.post0 pypi_0 pypi       
  python-gil 3.12.13 hd8ed1ab_0 conda-forge
  python-installer 1.0.1 pyh332efcf_0 conda-forge
  python-json-logger 4.1.0 pypi_0 pypi       
  python_abi 3.12 5_cp312 conda-forge
  pyzmq 27.1.0 pypi_0 pypi       
  readline 8.2 h8228510_1 conda-forge
  referencing 0.37.0 pypi_0 pypi       
  reproc 14.2.4.post0 hd590300_1 conda-forge
  reproc-cpp 14.2.4.post0 h59595ed_1 conda-forge
  requests 2.32.3 pyhd8ed1ab_0 conda-forge
  rfc3339-validator 0.1.4 pypi_0 pypi       
  rfc3986-validator 0.1.1 pypi_0 pypi       
  rfc3987-syntax 1.1.0 pypi_0 pypi       
  rpds-py 2026.6.3 pypi_0 pypi       
  ruamel.yaml 0.18.6 py312h98912ed_0 conda-forge
  ruamel.yaml.clib 0.2.8 py312h98912ed_0 conda-forge
  setuptools 74.1.2 pyhd8ed1ab_0 conda-forge
  simdjson 4.6.4 hb700be7_0 conda-forge
  six 1.17.0 pypi_0 pypi       
  sniffio 1.3.1 pyhd8ed1ab_2 conda-forge
  soupsieve 2.9.1 pypi_0 pypi       
  spdlog 1.17.0 hab81395_1 conda-forge
  stack-data 0.6.3 pypi_0 pypi       
  terminado 0.18.1 pypi_0 pypi       
  tinycss2 1.5.1 pypi_0 pypi       
  tk 8.6.13 noxft_h4845f30_101 conda-forge
  tomli 2.4.1 pyhcf101f3_0 conda-forge
  tornado 6.5.7 pypi_0 pypi       
  tqdm 4.66.5 pyhd8ed1ab_0 conda-forge
  traitlets 5.15.1 pypi_0 pypi       
  truststore 0.9.2 pyhd8ed1ab_0 conda-forge
  typing-extensions 4.16.0 h69aa097_0 conda-forge
  typing-inspection 0.4.2 pyhcf101f3_2 conda-forge
  typing_extensions 4.16.0 pyhcf101f3_0 conda-forge
  tzdata 2024a h8827d51_1 conda-forge
  unearth 0.18.2 pyhd8ed1ab_0 conda-forge
  uri-template 1.3.0 pypi_0 pypi       
  urllib3 2.2.3 pyhd8ed1ab_0 conda-forge
  wcwidth 0.8.2 pypi_0 pypi       
  webcolors 25.10.0 pypi_0 pypi       
  webencodings 0.5.1 pypi_0 pypi       
  websocket-client 1.9.0 pypi_0 pypi       
  wheel 0.44.0 pyhd8ed1ab_0 conda-forge
  widgetsnbextension 4.0.15 pypi_0 pypi       
  xz 5.8.3 ha02ee65_0 conda-forge
  xz-gpl-tools 5.8.3 ha02ee65_0 conda-forge
  xz-tools 5.8.3 hb03c661_0 conda-forge
  yaml-cpp 0.8.0 h59595ed_0 conda-forge
  zipp 4.1.0 pyhcf101f3_0 conda-forge
  zstandard 0.25.0 py312h5253ce2_1 conda-forge
  zstd 1.5.7 hb78ec9c_6 conda-forge

```

Bill Capehart  
South Dakota School of Mines

---

<div class="post-metadata">

**Author:** ![mahendrapaipuri](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/mahendrapaipuri/32/6800_2.png) [@mahendrapaipuri](https://discourse.jupyter.org/u/mahendrapaipuri)\
**Post date:** [July 31, 2026, 8:20am UTC](https://discourse.jupyter.org/t/tljh-service-stalling-on-login/38813/2 "2026-07-31T08:20:36Z")

</div>

Seems like some sort of compatibility issues between `libzmq` and `pyzmq`. Maybe you can try compiling `pyzmq` instead of using wheel as described [here](https://github.com/zeromq/pyzmq#building-and-installation). If not you can also try downgrading the `pyzmq` to a version `< 27.1.0`

---

<div class="post-metadata">

**Author:** ![wjcapehart](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/wjcapehart/32/6947_2.png) [@wjcapehart](https://discourse.jupyter.org/u/wjcapehart)\
**Post date:** [August 6, 2026, 7:47pm UTC](https://discourse.jupyter.org/t/tljh-service-stalling-on-login/38813/3 "2026-08-06T19:47:50Z")

</div>

Thank you Mahendra:

I was able to gtry one more time to install the system from scratch and this time I was able to get it to install and work.

Appropo of your recommendation I _did_ pull the working libraries for pymzq and libzmq:

From the base python environment for tljh:

pyzmq 27.1.0 py312hda471dd\_3 conda-forge

For libzmq via “apt”

```auto
Package: libzmq3-dev
Version: 4.3.5-1build2
Priority: optional
Section: universe/libdevel
Source: zeromq3
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Laszlo Boszormenyi (GCS) <gcs@debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 2,742 kB
Provides: libzmq5-dev
Depends: libzmq5 (= 4.3.5-1build2), libpgm-dev (>= 5.2.122~dfsg), libsodium-dev, libnorm-dev, libkrb5-dev, libbsd-dev
Recommends: cppzmq-dev
Conflicts: libzmq-dev, libzmq5-dev
Replaces: libzmq5-dev
Homepage: https://www.zeromq.org/
Download-Size: 527 kB
APT-Sources: http://us.archive.ubuntu.com/ubuntu noble/universe amd64 Packages
Description: lightweight messaging kernel (development files)
 ØMQ is a library which extends the standard socket interfaces with features
 traditionally provided by specialised messaging middleware products.
 .
 ØMQ sockets provide an abstraction of asynchronous message queues, multiple
 messaging patterns, message filtering (subscriptions), seamless access to
 multiple transport protocols and more.
 .
 This package contains the ZeroMQ development libraries and header files.

```

But for now we are back up and working.

Best Regards  
Bill Capehart  
South Dakota School of Mines