WP Admin folder restricted with IP but Ajax stopped working on front-end side

I’ll be precise, one of my client’s website is hosted on their internal server, and they have restricted the wp-admin folder to be accessed only by their internal network, and is now inaccessible by public, due to this, all ajax call/requests on front-end side has stopped working, i’m not sure what should i do? is there a way to access admin-ajax? or a work-around for ajax calls?

Any help is much appreciated.