Our suppliers are just getting a Please wait... message once they filled and submit the form

We've had 2 communications from our suppliers saying that when they click the submit button on our Musicians & Show form that it just comes up with "please wait" and then doesn't send the form through. 

I've tested it and it did say please wait but then sent the form to me after a few moments. I've changed the Submit button on the form but I can't see any way to fix the issue. Here's the link for the form - http://www.juliacharleseventmanagement.co.uk/content/musicians-and-shows-registration-form 

Please advise. Many thanks 

Hello michaelcharles,

I'm sorry for the trouble caused to you. 

Have you solved this problem already? I did test your form which is embedded in your webpage and I am unable to replicate the issue you are having. I was able to submit your form successfully. Please check the screenshot below:

I would suggest you to please test your form again and get back to us if the issue persists.

We will wait for your response.

Thank you!

Hello 

Thank you for coming back to me. I received your test form and have just tested it again and it has worked. I'm not sure why it wasn't working for our suppliers. I shall ask them to fill it in again and let you know if the issue persists. 

Many thanks 

You have six (6) upload fields in the form. The "Please wait..." message could be related to it. When images/videos are selected, the form will upload them first and the submit button will indicate this message before the form will be finally submitted. Your suppliers should wait for a little longer, especially if the video is in HD format. 

In some cases, the message indicates a possible script conflict, but the form has been embedded using our iframe method, so I don't think that's the case unless you've recently changed it.