My form is not allowing multiple submission even though I changed that

I'm having issues with the fact that my form is not allowing multiple submissions and I have it set to "no check" under that setting under preferences - advanced and I've changed it and saved it and it's still doing it. I don't understand what's going on. 

I have found one form in the link you provided, here is the link to the form: http://www.jotform.us/form/51820272775154 

I have just checked that form and noticed that you have disabled the options to limit submissions, both, based on the sender and based on question.

Indeed it is working, I have submitted twice your form without any problem, I was not able to see the data as it is encrypted, but, please check your submissions, you should find two submissions with text filled like "textbox_sample". 

If this is not the correct form, please share us the link to it, we will be glad to check it.