Re: unable to log in in iframes
Oh boy – just search these forums for integration.
https://bbpress.org/forums/tags/integration (threads tagged integration)
This was a good summary I thought:
http://www.adityanaik.com/integratepress-part-i/
Normally, people adjust the template of their forum to match their website. I haven’t seen one in an iframe yet, and don’t know enough about form submission (login form) and redirection and htaccess rewrite rules to know if it would work like that.