After customizing my portal theme and naming it to "portalcustom" theme, when I select &q

I am using "WHMCS Integration" plugin in my wordpress website. When I select the portal theme from WHMCS backend then all the functionalities inside the wordpress are working correctly but after customizing my portal theme and naming it to "portalcustom" theme, when I select "portalcustom" theme under WHMCS as a default theme then functionalities are not working in my wordpress website. I haven't changed the functionality inside the theme. I have updated only three files inside it which are "header.tpl", "footer.tpl", "style.css"."

Thanks