Mashed resend confirmation three times before I noticed
Welcome to the forum!
But I am afraid there is nothing we can do about this - email providers tend to mark emails from “unknown” addresses as spam.
I haven’t had this issue with Posteo, yet. I remember that we had a few related troubles with Delta Chat in the past, but however, they should be fixed by now.
@Pink Which version of Delta Chat are you using?
This is not an issue with Delta Chat but with this site here (if I understood correctly)