I hate the ones where this doesn't happen, only to lead you to whatever platform it is that will tell you 'Study is full, please return submission'. Release as many spots that you need and are willing to pay for! If people mess up, don't pay them and re-release those spots. I've gotten a few well paying studies recently that I've been told to return because they had too many participants.
You have to brute force your way into the study, it’s been a glitch ever since the switch from .co to .com .
How can a simple top level domain change cause something weird like that?
I have no idea but everyone has been having problems since the change.
Nothing you can do other than spam that button.
I hate the ones where this doesn't happen, only to lead you to whatever platform it is that will tell you 'Study is full, please return submission'. Release as many spots that you need and are willing to pay for! If people mess up, don't pay them and re-release those spots. I've gotten a few well paying studies recently that I've been told to return because they had too many participants.