"error on form" errors

in my form, there is not any require item and I dint put any conditions but

when I click send button, it says "there is error on your form"

what can I do ?

I looked at your form and found you actually do have 1 required field on your form which I can see at the top part of it. I tested your form and I am able to submit it so I think that you may have skipped the required field which was probably why. If you don't want it as required just go back into your form and turn that requirement off.