Login form not showing

I have set up a recurring event and selected: only available to logged in users. But when a user views the event on the site, it doesnt prompt them to login/register.

I would like the user to be prompted to register using one of the s2 membership packages I have set up.

I have ticked the box under Events, Settings, to say ‘show login form’ but it is not showing.

Please can you help?

thank you

https://wordpress.org/plugins/events-manager/