Hey guys,
i have a problem when executing twine check dist/*. Since I am completely new to publishing packages I cannot fix this error.
But one by one:

1. Your operating system: Mac OS
2. Version of python you are running:

python 3.7.6

3. How did you install twine? Did you use your operating system's package manager or pip or something else?

pip install twine

4. Version of twine you have installed (include complete output of):

twine version 3.7.1 (importlib_metadata: 4.10.0, pkginfo: 1.8.2, requests:
2.26.0, requests-toolbelt: 0.9.1, tqdm: 4.42.1)

5. Which package repository are you targeting?
   pypi

The Issue

Please describe the issue that you are experiencing.
After building the package with python3 -m build . a MANIFEST, ipypetrinet-1.0.0.tar.gz and UNKNOWN-0.0.0-py2.py3-none-any.whl file is successfully created. After that i tried twine check dist/* which throws the following error:

Checking dist/UNKNOWN-0.0.0-py2.py3-none-any.whl: InvalidDistribution: Invalid distribution metadata. 
This version of twine supports Metadata-Version 1.0, 1.1, 1.2, 2.0, 2.1, and 2.2

But when I unzip UNKNOWN-0.0.0-py2.py3-none-any.whl and look into the files, the only file containing the keyword Metadata-Version has an appropriate Metadata-Version of 2.1. To visualize this METADATA-file I will paste the first few lines below:

Metadata-Version: 2.1
Name: UNKNOWN
Version: 0.0.0
Summary: UNKNOWN
Home-page: UNKNOWN
License: UNKNOWN
Platform: UNKNOWN
Description-Content-Type: text/markdown
License-File: LICENSE.txt

Does anyone know how to deal with this?
Any help is appreciated! Thanks in advance.