remote kernel connection fails

Description

What steps will reproduce the problem?

Connect to remote kernel on linux server via instructions here. https://docs.spyder-ide.org/5/panes/ipythonconsole.html#using-external-kernels

This has previously been successful.

Traceback

Exception in comms call get_namespace_view:
  File "C:\WPy64-31241\python-3.12.4.amd64\Lib\site-packages\spyder_kernels\comms\commbase.py", line 317, in _comm_message
    buffer = cloudpickle.loads(msg['buffers'][0],
                               ~~~~~~~~~~~~~~^^^
IndexError: list index out of range
Exception in comms call get_var_properties:
  File "C:\WPy64-31241\python-3.12.4.amd64\Lib\site-packages\spyder_kernels\comms\commbase.py", line 317, in _comm_message
    buffer = cloudpickle.loads(msg['buffers'][0],
                               ~~~~~~~~~~~~~~^^^
IndexError: list index out of range
Exception in comms call is_special_kernel_valid:
  File "C:\WPy64-31241\python-3.12.4.amd64\Lib\site-packages\spyder_kernels\comms\commbase.py", line 317, in _comm_message
    buffer = cloudpickle.loads(msg['buffers'][0],
                               ~~~~~~~~~~~~~~^^^
IndexError: list index out of range

Versions

Spyder version: 5.5.5 (pip)
Python version: 3.12.4 64-bit
Qt version: 5.15.2
PyQt5 version: 5.15.10
Operating System: Windows-11-10.0.22631-SP0

Dependencies

# Mandatory:
atomicwrites >=1.2.0             :  1.4.0 (OK)
chardet >=2.0.0                  :  5.2.0 (OK)
cloudpickle >=0.5.0              :  3.0.0 (OK)
cookiecutter >=1.6.0             :  2.6.0 (OK)
diff_match_patch >=20181111      :  20200713 (OK)
intervaltree >=3.0.2             :  3.0.2 (OK)
IPython >=8.13.0,<9.0.0,!=8.17.1 :  8.25.0 (OK)
jedi >=0.17.2,<0.20.0            :  0.19.1 (OK)
jellyfish >=0.7                  :  1.0.3 (OK)
jsonschema >=3.2.0               :  4.19.2 (OK)
keyring >=17.0.0                 :  25.2.1 (OK)
nbconvert >=4.0                  :  7.16.1 (OK)
numpydoc >=0.6.0                 :  1.6.0 (OK)
paramiko >=2.4.0                 :  2.8.0 (OK)
parso >=0.7.0,<0.9.0             :  0.8.4 (OK)
pexpect >=4.4.0                  :  4.8.0 (OK)
pickleshare >=0.4                :  0.7.5 (OK)
psutil >=5.3                     :  5.9.8 (OK)
pygments >=2.0                   :  2.18.0 (OK)
pylint >=3.1,<4                  :  3.1.0 (OK)
pylint_venv >=3.0.2              :  3.0.3 (OK)
pyls_spyder >=0.4.0              :  0.4.0 (OK)
pylsp >=1.11.0,<1.12.0           :  1.11.0 (OK)
pylsp_black >=2.0.0,<3.0.0       :  2.0.0 (OK)
qdarkstyle >=3.2.0,<3.3.0        :  3.2.3 (OK)
qstylizer >=0.2.2                :  0.2.2 (OK)
qtawesome >=1.3.1,<1.4.0         :  1.3.1 (OK)
qtconsole >=5.5.1,<5.6.0         :  5.5.2 (OK)
qtpy >=2.1.0                     :  2.4.1 (OK)
rtree >=0.9.7                    :  1.1.0 (OK)
setuptools >=49.6.0              :  69.5.1 (OK)
sphinx >=0.6.6                   :  7.2.6 (OK)
spyder_kernels >=2.5.2,<2.6.0    :  2.5.2 (OK)
textdistance >=4.2.0             :  4.5.0 (OK)
three_merge >=0.1.1              :  0.1.1 (OK)
watchdog >=0.10.3                :  2.2.0 (OK)
zmq >=24.0.0                     :  26.0.3 (OK)

# Optional:
cython >=0.21                    :  3.0.10 (OK)
matplotlib >=3.0.0               :  3.9.0 (OK)
numpy >=1.7                      :  1.26.4 (OK)
pandas >=1.1.1                   :  2.2.2 (OK)
scipy >=0.17.0                   :  1.13.1 (OK)
sympy >=0.7.3                    :  1.12.1 (OK)

Environment

``` Package Version ----------------------------- ------------------- about-time 4.2.1 absl-py 2.0.0 accelerate 0.28.0 adbc-driver-manager 0.11.0 adodbapi 2.6.1.3 affine 2.3.1 aiofiles 23.2.1 aiohttp 3.9.5 aiosignal 1.3.1 aiosqlite 0.20.0 alabaster 0.7.16 alembic 1.13.1 alive-progress 3.1.5 altair 5.3.0 altair-data-server 0.4.1 altair-transform 0.2.0 aniso8601 9.0.1 annotated-types 0.6.0 ansicolors 1.1.8 anyio 4.4.0 anywidget 0.9.12 appdirs 1.4.4 argon2-cffi 23.1.0 argon2-cffi-bindings 21.2.0 array_api_compat 1.7.1 arrow 1.2.2 asgi-csrf 0.9 asgiref 3.8.1 asn1crypto 1.5.1 asteval 0.9.31 astroid 3.1.0 astropy 6.1.0 astropy-iers-data 0.2024.4.29.0.28.48 asttokens 2.4.1 async-lru 2.0.4 async-timeout 4.0.3 atomicwrites 1.4.0 attrs 23.2.0 autograd 1.6.2 autopep8 2.0.4 azure-core 1.30.1 azure-cosmos 4.6.0 azure-identity 1.16.0 Babel 2.15.0 baresql 0.8.0 bcrypt 4.0.1 beautifulsoup4 4.12.2 binaryornot 0.4.4 black 24.4.2 bleach 6.1.0 blinker 1.7.0 bokeh 3.4.1 botorch 0.9.5 branca 0.7.2 Brotli 1.1.0 build 1.2.1 cachelib 0.13.0 cachetools 5.3.3 Cartopy 0.23.0 certifi 2024.6.2 cffi 1.16.0 cftime 1.6.3 chardet 5.2.0 charset-normalizer 3.3.2 clarabel 0.9.0 click 8.1.7 click-default-group 1.2.4 click-plugins 1.1.1 cligj 0.7.2 cloudpickle 3.0.0 clr-loader 0.2.6 clrmagic 0.0.1a2 cma 3.2.2 colorama 0.4.6 colorcet 3.1.0 colorlog 6.8.2 comm 0.2.2 contourpy 1.2.1 cookiecutter 2.6.0 coverage 7.5.3 cryptography 41.0.5 cvxopt 1.3.2 cvxpy 1.5.0 cycler 0.12.1 Cython 3.0.10 cytoolz 0.12.3 dash 2.17.0 dash-core-components 2.0.0 dash-html-components 2.0.0 dash-table 5.0.0 dask 2024.5.2 dask-expr 1.1.2 dask-image 2024.5.3 datasette 0.64.6 datasette-graphql 2.2 datashader 0.16.2 db.py 0.5.4b1 deap 1.4.1 debugpy 1.8.0 decorator 4.4.2 defusedxml 0.7.1 Deprecated 1.2.13 diff-match-patch 20200713 dill 0.3.7 dirty-cat 0.4.1 distlib 0.3.8 distributed 2024.5.2 distro 1.8.0 Django 5.0.6 dnspython 2.6.1 docopt 0.6.2 docstring-to-markdown 0.13 docutils 0.20.1 duckdb 1.0.0 ecos 2.0.13 email_validator 2.1.1 entrypoints 0.4 et-xmlfile 1.1.0 executing 2.0.1 fast-histogram 0.14 fastapi 0.111.0 fastapi-cli 0.0.4 fastjsonschema 2.18.0 filelock 3.14.0 filterpy 1.4.5 fiona 1.9.5 flake8 7.0.0 Flask 3.0.3 Flask-Mail 0.9.1 Flask-Session 0.5.0 Flask-SQLAlchemy 3.0.5 flit 3.9.0 flit_core 3.9.0 folium 0.16.0 fonttools 4.51.0 formlayout 1.2.1a1 fqdn 1.5.1 frozenlist 1.4.1 fsspec 2024.3.1 future 0.18.2 fuzzywuzzy 0.18.0 GDAL 3.7.3 geographiclib 2.0 geopandas 0.14.4 geopy 2.4.1 gitdb 4.0.10 GitPython 3.1.32 gpytorch 1.11 grapheme 0.6.0 graphene 3.3 graphql-core 3.2.3 graphql-relay 3.2.0 greenlet 3.0.3 guidata 3.5.0 h11 0.14.0 h2 4.1.0 h5py 3.10.0 hatchling 1.24.2 holoviews 1.19.0 hpack 4.0.0 html5lib 1.1 httpcore 1.0.5 httpie 3.2.2 httptools 0.6.1 httpx 0.27.0 huggingface-hub 0.23.0 hupper 1.12 hvplot 0.10.0 Hypercorn 0.16.0 hyperframe 6.0.1 hypothesis 6.100.5 idna 3.7 imageio 2.33.1 imageio-ffmpeg 0.4.8 imagesize 1.4.1 imbalanced-learn 0.12.3 importlib_metadata 7.1.0 inflection 0.5.1 iniconfig 2.0.0 intervaltree 3.0.2 ipycanvas 0.13.2 ipykernel 6.29.4 ipyleaflet 0.19.1 ipympl 0.9.4 ipython 8.25.0 ipython-genutils 0.2.0 ipython-sql 0.5.0 ipywidgets 8.1.2 isoduration 20.11.0 isort 5.13.2 itsdangerous 2.2.0 janus 1.0.0 jaraco.classes 3.4.0 jaraco.context 5.3.0 jaraco.functools 4.0.1 jaxtyping 0.2.22 jedi 0.19.1 jellyfish 1.0.3 Jinja2 3.1.2 joblib 1.4.2 json5 0.9.14 jsonpatch 1.33 jsonpointer 2.4 jsonschema 4.19.2 jsonschema-specifications 2023.12.1 julia 0.6.2 jupyter 1.0.0 jupyter_bokeh 4.0.5 jupyter_client 8.6.2 jupyter-console 6.6.3 jupyter_core 5.7.2 jupyter-events 0.10.0 jupyter-leaflet 0.19.1 jupyter-lsp 2.2.5 jupyter_server 2.14.1 jupyter_server_terminals 0.5.3 jupyterlab 4.2.2 jupyterlab_pygments 0.3.0 jupyterlab_server 2.27.2 jupyterlab_widgets 3.0.11 keras 3.3.3 keyring 25.2.1 kiwisolver 1.4.5 kornia 0.7.2 kornia_rs 0.1.3 langchain 0.2.5 langchain-core 0.2.7 langchain-text-splitters 0.2.1 langsmith 0.1.77 lazy_loader 0.4 lightning 2.2.1 lightning-utilities 0.10.0 linear-operator 0.5.1 linkify-it-py 2.0.2 llvmlite 0.43.0 lmfit 1.3.1 locket 1.0.0 lxml 5.2.2 Mako 1.2.0 Markdown 3.5.1 markdown-it-py 2.2.0 MarkupSafe 2.1.1 matplotlib 3.9.0 matplotlib-inline 0.1.7 maturin 1.5.1 mccabe 0.7.0 mdit-py-plugins 0.3.5 mdurl 0.1.2 mercantile 1.2.1 mergedeep 1.3.4 missingno 0.5.1 mistune 2.0.5 mizani 0.11.4 ml-dtypes 0.4.0 mlxtend 0.22.0 more-itertools 10.2.0 moviepy 1.0.3 mpl-scatter-density 0.7 mpld3 0.5.8 mpmath 1.3.0 msal 1.24.1 msal-extensions 1.0.0 msgpack 1.0.4 msvc_runtime 14.40.33807 multidict 6.0.5 multipledispatch 1.0.0 mutagen 1.47.0 mypy 1.10.0 mypy-extensions 1.0.0 mysql-connector-python 8.0.21 namex 0.0.8 nbclient 0.10.0 nbconvert 7.16.1 nbformat 5.10.4 nest-asyncio 1.6.0 netCDF4 1.6.5 networkx 3.3 nltk 3.8.1 notebook 7.2.1 notebook_shim 0.2.4 ntlm-auth 1.5.0 numba 0.60.0 numexpr 2.10.0 numpy 1.26.4 numpydoc 1.6.0 openai 1.33.0 opencv-python 4.10.0.82 openpyxl 3.1.2 opt-einsum 3.3.0 optree 0.11.0 optuna 3.6.1 orjson 3.9.15 ortools 9.8.3296 outcome 1.3.0.post0 overrides 7.7.0 packaging 24.1 pandas 2.2.2 pandocfilters 1.5.0 panel 1.4.4 papermill 2.6.0 param 2.1.0 paramiko 2.8.0 parso 0.8.4 partd 1.4.0 pathspec 0.11.0 patsy 0.5.6 pdfrw 0.4.post2 pep8 1.7.1 pexpect 4.8.0 pg8000 1.23.0 pickleshare 0.7.5 pillow 10.3.0 PIMS 0.6.1 Pint 0.23 pip 24.0 pkginfo 1.9.6 platformdirs 4.2.2 plotly 5.22.0 plotnine 0.13.6 PlotPy 2.3.0 pluggy 1.5.0 ply 3.11 pmdarima 2.0.4 polars 0.20.31 portalocker 2.7.0 portpicker 1.5.0 ppci 0.5.9 prettytable 3.3.0 priority 2.0.0 proglog 0.1.10 prometheus-client 0.18.0 prompt-toolkit 3.0.43 protobuf 4.25.1 psutil 5.9.8 psygnal 0.11.1 ptpython 3.0.26 ptyprocess 0.7.0 PuLP 2.6.0 pure-eval 0.2.2 pyarrow 16.1.0 PyAudio 0.2.14 pybars3 0.9.7 pybind11 2.12.0 pycodestyle 2.11.1 pycosat 0.6.6 pycparser 2.22 pycryptodomex 3.20.0 pyct 0.5.0 pydantic 2.7.1 pydantic_core 2.18.2 pydeck 0.9.1 pydocstyle 6.3.0 pydub 0.25.1 pyepsg 0.4.0 pyerfa 2.0.1.4 pyflakes 3.2.0 pygame 2.5.2 Pygments 2.18.0 PyJWT 2.8.0 pylint 3.1.0 pylint-venv 3.0.3 pyls-spyder 0.4.0 PyMeta3 0.5.1 pymongo 4.7.2 pymoo 0.6.1.1 Pympler 1.0.1 PyNaCl 1.5.0 pynndescent 0.5.12 pyodbc 5.1.0 Pyomo 6.7.2 pypandoc 1.5 pyparsing 3.1.2 pypdf 3.15.2 pypng 0.20220715.0 pyproj 3.6.1 pyproject_hooks 1.1.0 PyQt5 5.15.10 PyQt5-Qt5 5.15.2 PyQt5-sip 12.13.0 pyqtgraph 0.13.7 PyQtWebEngine 5.15.6 PyQtWebEngine-Qt5 5.15.2 pyro-api 0.1.2 pyro-ppl 1.9.0 pyserial 3.5 pyshp 2.3.1 PySimpleGUI 4.60.4 PySocks 1.7.1 pytest 8.2.0 python-barcode 0.15.1 python-dateutil 2.8.2 python-dotenv 1.0.1 python-json-logger 2.0.7 python-lsp-black 2.0.0 python-lsp-jsonrpc 1.1.2 python-lsp-server 1.11.0 python-multipart 0.0.9 python-slugify 6.1.2 pythonnet 3.0.3 PythonQwt 0.12.1 pytoolconfig 1.3.1 pytorch-lightning 2.2.1 pytz 2023.3 pytz-deprecation-shim 0.1.0.post0 pyviz_comms 3.0.2 pywin32 306 pywin32-ctypes 0.2.2 pywinpty 2.0.12 pywinusb 0.4.2 PyYAML 6.0.1 pyzmq 26.0.3 QDarkStyle 3.2.3 qpsolvers 4.3.0 qrcode 7.4.2 qstylizer 0.2.2 QtAwesome 1.3.1 qtconsole 5.5.2 QtPy 2.4.1 quantecon 0.5.3 Quart 0.19.4 rapidfuzz 3.5.2 rasterio 1.3.10 readme-renderer 35.0 redis 4.3.1 referencing 0.31.1 regex 2023.10.3 reportlab 4.2.0 requests 2.31.0 requests-ntlm 1.1.0 requests-toolbelt 1.0.0 retrying 1.3.4 rfc3339-validator 0.1.4 rfc3986 2.0.0 rfc3986-validator 0.1.1 rich 13.7.1 rope 1.12.0 rpds-py 0.13.2 Rtree 1.1.0 Rx 3.1.1 safetensors 0.4.2 scikit-image 0.23.2 scikit-learn 1.5.0 scipy 1.13.1 scramp 1.4.1 scs 3.2.4.post1 seaborn 0.13.2 Send2Trash 1.8.2 setuptools 69.5.1 shapely 2.0.4 shellingham 1.5.0.post1 simplegeneric 0.8.1 simplejson 3.19.2 simpy 4.0.1 six 1.16.0 slicerator 1.1.0 smmap 5.0.0 sniffio 1.3.0 snowballstemmer 2.2.0 snuggs 1.4.7 sortedcontainers 2.4.0 sounddevice 0.4.6 soupsieve 2.5 Sphinx 7.2.6 sphinx-rtd-theme 2.0.0 sphinxcontrib-applehelp 1.0.2 sphinxcontrib-devhelp 1.0.2 sphinxcontrib-htmlhelp 2.0.0 sphinxcontrib-jquery 4.1 sphinxcontrib-jsmath 1.0.1 sphinxcontrib-qthelp 1.0.3 sphinxcontrib-serializinghtml 1.1.9 spyder 5.5.5 spyder-kernels 2.5.2 SQLAlchemy 2.0.28 sqlite_bro 0.13.1 sqlite-fts4 1.0.3 sqlite-utils 3.36 sqlparse 0.4.3 sspyrs 0.3 stack-data 0.6.3 starlette 0.37.2 statsmodels 0.14.2 streamlit 1.35.0 streamz 0.6.3 swifter 1.3.4 sympy 1.12.1 tabulate 0.9.0 tbats 1.1.0 tblib 1.7.0 tenacity 8.1.0 terminado 0.18.1 text-unidecode 1.3 textdistance 4.5.0 threadpoolctl 3.5.0 three-merge 0.1.1 tifffile 2023.7.18 tinycss2 1.1.1 tokenizers 0.15.1 toml 0.10.2 tomli 2.0.1 tomli_w 1.0.0 tomlkit 0.12.3 toolz 0.12.0 torch 2.2.2 torchaudio 2.2.2 torchmetrics 1.3.2 torchvision 0.17.2 tornado 6.4 tqdm 4.66.4 traitlets 5.14.1 traittypes 0.2.1 transformers 4.38.2 trio 0.25.1 trove-classifiers 2023.2.20 twine 4.0.1 typeguard 2.13.3 typer 0.12.3 typing_extensions 4.9.0 tzdata 2022.7 tzlocal 4.2 uc-micro-py 1.0.1 ujson 5.8.0 umap-learn 0.5.1 uncertainties 3.1.7 uri-template 1.2.0 urllib3 2.0.3 uvicorn 0.29.0 vega-datasets 0.9.0 virtualenv 20.26.2 waitress 2.1.2 wasmer 1.1.0 wasmer-compiler-cranelift 1.1.0 wasmer-compiler-singlepass 1.1.0 watchdog 2.2.0 watchfiles 0.21.0 wcwidth 0.2.13 webcolors 1.12 webencodings 0.5.1 websocket-client 1.8.0 websockets 12.0 Werkzeug 3.0.3 whatthepatch 1.0.2 wheel 0.43.0 widgetsnbextension 4.0.10 winpython 8.2.20240618 wordcloud 1.9.3 wrapt 1.14.1 wsproto 1.2.0 xarray 2024.6.0 XlsxWriter 3.1.9 xlwings 0.24.7 xmltodict 0.13.0 xyzservices 2023.10.1 yapf 0.40.1 yarl 1.7.2 yt-dlp 2023.7.6 zict 3.0.0 zipp 3.17.0 zstandard 0.22.0 ```

spyder-ide / spyder