I deleted my submission and I still cannot submit

Yes, this worked but my form is used monthly. Is there a way to reset (delete the cookies) upon deleting each months submissions? So attendees can still sign up next month without being blocked. I tested this and when I deleted my submission and tried to sign up again I still was blocked.

Getting it to clear cookies or reset on deletion would be a great help.

If the Unique Submission is set to "Check cookies only", then it will still work if you use another browser or you clear the cache and cookies of the browser.

It is possible that you set it to "Check cookies and IP" when you tried this feature. If you do this, then even if you clear the browser cache, the user still cannot submit the form because it is blocked by IP address. You need to delete the submissions of that user in order to submit a new one.

I suggest you check the Unique Question feature too, here's a guide: How-to-set-Form-Limits-Based-on-a-Unique-Question.

Hope that helps. Thank you.