Mobile Menu Bar Navigation Links Disappeared

I suddenly discovered that the navigation links in the menu bar using mobile devices to view the website suddenly disappeared in these couple of days.

Problem is attached.

Does any expert could help in this issue?

Thank you.

www.proedforce.com

@PROEF Which device did you use? Seems fine here.

@tuanphan iPhone 6, iphone 6S and iphone XR occur the same problem.

I have tried to remove any programming codes yet the problem still exist.

Try adding this code to Design> Custom CSS

@media only screen and (max-width: 768px) {
body.mobile-menu-open .overflow-wrapper {
    position: inherit !important;
}
}

@christyprice There is an error message as shown when I put the code into Custom CSS. How can I fix this?

Thank you.

@PROEF @christypriceThe code should be

@media only screen and (max-width: 768px) {
body.mobile-menu-open .overflow-wrapper {
    position: inherit !important;
}
}

@tuanphan @christyprice

Thank you for both of your advice. The problem is now fixed after inserting the CSS code.