Fix Persistent Login Bug

I need a developer to troubleshoot and repair a functionality issue that is blocking every user from logging in or registering on my site. The failure happens every single time, so you should be able to reproduce it immediately and trace the root cause without waiting for an intermittent glitch... (Budget: £20 - £250 GBP, Jobs: Debugging, JavaScript, MySQL, PHP, Software Testing, Troubleshooting, Web Development, WordPress)