plugin won't install – any ideas?

I’ve tried to install the plugin into my www.ads-software.com backend three times now, and I have gotten the same error message each time:

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Downloading install package from https://downloads.www.ads-software.com/plugin/wordfence.6.0.22.zip…

Unpacking the package…

Could not create directory.

Return to Plugin Installer

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I can’t tell what the problem is. I have other plugins, so directories should not be an issue. Any ideas? Has there been any reported cases of installation error due to a conflict between Wordfence and an already installed plugin?

Thanks in advance.

https://www.ads-software.com/plugins/wordfence/