I've installed Q&A Plugin on a WordPress Multisite install

Hi,

I've installed Q&A Plugin on a WordPress Multisite install (Network Admin -> Plugins and Network Activate the plugin)
I'm also using PRO sites plugin.
The problem I'm facing is that there does not seem to be a "visitor" role (error msg "[Q&A] Visitor role cannot be found. Try to deactivate and reactivate the plugin, if you continue to see this message, consult our Help and Support.")
So I've deactivated and reactivated the plugin... still same issue.

How could I fix this?

Thanks,

Regards,

DG