I have this same problem, not getting the login code by email.
I don't know how to edit php and I also like the security, so how can I fix?
Also there is no "resend code" button?
How do I use the "backup code?" None of them work.
I have hostgator. I can reach out to them.
A few weeks ago forum went down and I called them. They told me the only way to get it back up was to revert to an older version of php. I knew that probably wasn't cool, but it got the site back up. I'm betting the problem is related.
OK I am going to need help I guess.
It's actually something I am going to have to figure out. You can't manage an XF forum with no real knowledge. You can pretty much handle a wordpress site (the rest of my site) without much knowledge.