php form

[ACBeecher]

I have two basic form pages, for example https://www.artegousa.com/FillInForm.php
People complete them all the time but frequently people email me that they tried to use the form(s) several times
and always got an error. Of course, I have no idea what the error was. Any idea what causes the errors? Or what fixes I can try?
Thank you.

[Pablo]

It is difficult to help you if I do not know what the error is.
I need more details.