https not working with my custom domain

I have been able to set my custom domain, but it seems I can only use it withough the s in http, 

working: http://form.kgrouptravel.com/60683640185963

not worling: https://form.kgrouptravel.com/60683640185963

I´m not too techy, but do now this has to do with the security of the form and in some of my sorms I do collect info that want to keep secure. Is there something else that I need to do in orther for the https to work?

Since you are using custom domain, it is required to have an SSL certificate installed for your domain in order to access your forms with https. Also, you may need a separate certificate or Wild card SSL certificate since the forms are being accessed using a sub-domain form. If you want to use https with your domain, you may get in touch with your hosting service provider for more information in this regard.

Hope this information helps!