Cannot submit application???????

Cannot submit application???????

Could U please help check the form below:

https://creator.zoho.com/pashanoi/form/25
It runs quite well with my IP, but some of my customers cannot submit the registration form. After they fill out the form and click Submit button, no result show up, just have a message "please wait" but it is still the form with their database.

Thanks a lot,

P/s: this is very urgent, hope to receive your reply as soonest as possible.