[fshbrsh]

Is there a plugin or modification I can do that will show the login field for topics that are private?

We send newsletters with links to topics, and unless a user is logged in they see the 404 error page.

I have resolved this by having the 404 page show the login field. However, I do not want that to appear on actual 404 pages.

Is there a membership plugin that will allow me to specify what is shown when a user is not logged in and they try to access a private topic?

[Robin W]

try my private groups plugin

https://wordpress.org/plugins/bbp-private-groups/