New patron cannot login for a while

I am planning on launching my Patreon page very soon. I created Patron accounts and signed up myself for test purposes to make sure everything will work fine.
Every time I try to login to my site as a Patron, I can’t login for the first 10-15 minutes after signing up. And after that everything works fine. It’s probably not a big deal if I just tell the new patrons that they have to wait for a while before logging in, but just wondered if there was a way to fix it.
Thank you!

You cant login for the first 10-15 minutes after you sign up?

Check any caching plugin that you may have at your site and whether they are set to aggressive. Also server-side caching.