Flit fail when trying to upload a minimal package:

[project]
name = "epot-test"
description = "aaa"
readme = "README.md"
requires-python = ">=3.7"
authors = [{name = "Conchylicultor", email="[email protected]"}]
dynamic = ["version"]

[build-system]
requires = ["flit_core >=3.5,<4"]
build-backend = "flit_core.buildapi"

Commands:

flit build
flit publish

flit publish fails with:

epot-macbookpro2:epot-test epot$ flit publish
Found 8 files tracked in git                                                                                   I-flit.sdist
Built sdist: dist/epot-test-1.1.0.tar.gz                                                                  I-flit_core.sdist
Copying package file(s) from /var/folders/67/mbgvk_q96wd9hmdgm8z9ts4r00fsh4/T/tmpgkxoru5_/epot-test-1.1.0/epot-test  I-flit_core.wheel
Writing metadata files                                                                                    I-flit_core.wheel
Writing the record of files                                                                               I-flit_core.wheel
Built wheel: dist/epot_test-1.1.0-py3-none-any.whl                                                        I-flit_core.wheel
Using repository at https://upload.pypi.org/legacy/                                                           I-flit.upload
Uploading dist/epot_test-1.1.0-py3-none-any.whl...                                                            I-flit.upload
Traceback (most recent call last):
  File "/Users/epot/.pyenv/versions/3.10.0/bin/flit", line 8, in <module>
    sys.exit(main())
  File "/Users/epot/.pyenv/versions/3.10.0/lib/python3.10/site-packages/flit/__init__.py", line 185, in main
    main(args.ini_file, repository, args.pypirc, formats=set(args.format or []),
  File "/Users/epot/.pyenv/versions/3.10.0/lib/python3.10/site-packages/flit/upload.py", line 268, in main
    do_upload(built.wheel.file, built.wheel.builder.metadata, pypirc_path, repo_name)
  File "/Users/epot/.pyenv/versions/3.10.0/lib/python3.10/site-packages/flit/upload.py", line 246, in do_upload
    upload_file(file, metadata, repo)
  File "/Users/epot/.pyenv/versions/3.10.0/lib/python3.10/site-packages/flit/upload.py", line 239, in upload_file
    resp.raise_for_status()
  File "/Users/epot/.pyenv/versions/3.10.0/lib/python3.10/site-packages/requests/models.py", line 960, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 400 Client Error: Invalid value for provides. Error: Use a valid Python identifier. for url: https://upload.pypi.org/legacy/

flit --version is Flit 3.7.1

It's very non obvious from the error message what is the issue with my toml file. It would be nice to have more explicit error messages.