So for some reason, you're triggering an AJAX request on form submission. I'm not going to ask why, but I'm going to give you a little insight to your imminent doom. Everything looks good across multiple browsers. No issues on mobile devices. We're good to go, let's get this baby out to production. Suddenly, you hear the dreaded..
Some users are reporting issues.
What, only some users? How is that even possible? Well, turns out that when you trigger an asynchronous AJAX request on form submission, there's a chance that it never actually gets sent out. That's because there's a chance the page has already unloaded by the time it actually goes to send.
The simplest, immediate solution is to change your AJAX request over to be synchronous. This way the browser will make sure the request is actually fired before proceeding to submit the form.
Phew. Lucky you didn't actually deploy that to production right?