I don't recall a bug on this for the current version
It sounds like what is happening is you have Enable Email Verification turned on.
When it is turned on the email from that user is reserved for a while.
Possibly your authentication emails are not being sent.
Anyway it should be in ubb cp-membership -members -tab registration queue
Or it could be a true duplicate.
Which you can search for the email in ubb cp membership-members
Which sounds like what you are doing.
What version are you using?
Also a url to your site may be helpful.
Your profile has a broken url for homepage.
Last edited by Ruben; 10/25/2019 1:29 PM.
