Having tested the plugin on my test site, I tried to then install on my live site and I got an error as per the attached screen shot.
Tried again and got same error.
So I installed by copying across the copy from my test site.
No idea why this is.
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This is problem with WordPress.org, there is nothing I can do about it. Usually this error goes away on it’s own, it is temporary problem. If it continues, install plugin manually.
Dev4Press - Premium plugins for WordPress.