For those having issues getting the email form to:
Show up at all
Submit once/if it is showing up
Disable your ad and tracker blockers for syncapps.io.
iFor me, AdGuard was blocking the form from showing up at all. Then, in Firefox, dev tools showed that the tracker tool was stopping the form from submitting. Once I disabled both things for the site, I was (hopefully) able to get it submitted. I got the "Thanks for signing up" notification on the site, anyway. I'm not sure if I was supposed to receive a confirmation email, so I'm just hopeful it worked.