No Off Canvas Menu on Mobile

I am unable to get the off canvas menu to display on a mobile phone on JA Spa. Can someone assist please?

Thanks.

cspgsl
Hi
Kindly submit your site admin URL. /administrator redirect back to Homepage.

done.

thanks.

cspgsl
Hi
This issue is due to custom css
Remove this code

*, *::before, *::after {
    box-sizing: content-box;
}

from custom css file and check.

Thanks, that worked

cspgsl
You are welcome!