QGIS 3.18.2: ModuleNotFoundError: No module named 'supy'

starting QGIS I get the error:

Konnte Erweiterung ‘processing_umep’ nicht laden aufgrund eines
Fehlers beim Aufruf der classFactory() Methode

ModuleNotFoundError: No module named ‘supy’

Traceback (most recent call last): File
"/Applications/QGIS.app/Contents/MacOS/../Resources/python/qgis/utils.py",
line 335, in _startPlugin

plugins[packageName] = package.classFactory(iface)

:

:

etc

But when I try to install supy

sudo -H pip install supy

I am informed that supy is already installed and that all "Requirement already satisfied".

What can I do?

---

Python-Version: 3.8.7 (default, Feb 10 2021, 09:04:08) [Clang 12.0.0 (clang-1200.0.32.29)]

QGIS-Version: 3.18.2-Zürich Zürich, 44d7dfabbe

OS: macOS Big Sur 11.3.1