TML and iframes- PLEASE HELP!

I just received an email from my web designer that he is unable to open my website login in an iframe…any reason why?

i.e. http://www.mysite.com/login (using Theme My Login Plugin)

He can open up any other page on my site without any problem.

Please Help!!

thank!

https://wordpress.org/plugins/theme-my-login/

[Moderator Note: No bumping, thank you.]