Hi there!
Thanks for reaching out.
I just checked your website, and the off-canvas menu appears to be working correctly. I tested it both on a mobile device and through the browser's responsive inspection tools.
Could you please let me know if there is any specific scenario or condition under which the issue occurs? If possible, please also share a screenshot or short screencast showing the issue.
Regarding the domain name, you can replace the existing/old domain with the new one by using the Edit option. There is no separate Delete option, but you can simply edit the existing domain and replace it with the new one.
Best regards,