Solved Kunena login - log in works, registration triggers 404 error?

still not working I followed the video exactly, restored Kunena menu, etc. etc. and still registration throws a 404. I can log in as admin (from frontend) but cannot register new users)

Have you tried to build a completely new site for testing, following the guide given in When all else fails, try this .

One point that we have to be absolutely clear about is this:
If you have a standard Joomla configuration and you can register new users with a standard Joomla configuration then adding Kunena should not affect the ability for people to register on your website. If you have changed the Joomla configuration in some way and people cannot register at your website then I do not think this is a problem caused by Kunena. If you want to prove this, beyond any doubt, uninistall Kunena from your website and see if people encounter these 404 errors.

Ok, seems the problem is/was with K2 component. I've now uninstalled all K2 elements and the login/registration is working. Thank you.

Please read docs.kunena.org/index.php/Kunena_Feature...er_Joomla_extensions

So I see
I wasn't using K2 anyway; it was installed previously and unused so no loss and problem solved. Thanks so much for the very speedy responses and help. Much appreciated.

There are three things you should do to try and find where the problem lies:
1 - switch to one of the default Joomla templates
2 - switch to the standard Kunena template
3 - turn off SEF

Try a clean install based on these three changes, then you can re-introduce these things one at a time, testing thoroughly between each one. Hopefully that way you will discover which one is causing your problem.