Forms not working on mobile phones

Recently our customers have been telling us that the links we put in our forms are not working. When we tried them they would work. Then we discovered that the links to the forms work well when clicked on a PC, or a laptop but NOT from mobile phones. I tried it myself and the links don't work from a cell phone. Is that normal?

I want to know if we are doing something wrong or if the links simply are not made to work from cell phones, even though we never got any complaints before, until a couple of months ago. Otherwise everything works ok.

All our forms are mobile responsive by default and they should work on all mobile devices. 

Please provide us a link of your form so that we can test it. If your form is embedded, provide us the webpage URL.