OK I think I have identified the problem and it is not your plugin! 🙂 Thank you for your help.
Yes, this is checked. What is happening is that the link for the register and login pages are just not loading resulting in 405 or 504 errors. It is fairly erratic as sometimes you can click the link and it loads ok and then if you go back to the links the errors occur. The website is http://www.bid4yourwebsite.com
Thanks.
