Plugin installation failed

Hi!
Because of big problems I uninstalled the plugin. Now I want to install it again as a test, but it does not work. It always comes the following error message:
“The package could not be installed. No working plugins were found. Plugin installation failed.”
I followed these instructions:
https://villatheme.com/knowledge-base/download-and-install-villatheme-plugins/
And I also tried to install the plugin manually via FTP on the server. Nothing works.
Yes, Woocommerce is installend.
Yes, I downloaded the installable WordPress file only.
Please help!