Opens in new blank page instead of popup

Hello there, there seems to be a problem with the call back request script, it opens a new blank page with form and a bad css! Please check it on https://www.nagpurcityhomes.com/ . I tried disabling some other plugins which might conflict with its scripts but still of no help!

Hoping for your help

Thanks in advance

https://www.ads-software.com/plugins/request-call-back/