Hi @malenaamer! Are you running QIIME 2 on a server somewhere that doesn’t have a display attached to it? If not, you don’t need to worry about the echo "backend: Agg" > ~/.config/matplotlib/matplotlibrc command. If you are installing QIIME 2 in a headless environment (no display, e.g. desktop GUI), then you need to make sure that the necessary directories are in place before running that command:
$ mkdir -p ~/.config/matplotlib
$ echo "backend: Agg" > ~/.config/matplotlib/matplotlibrc
Hope that helps!