I have the following problem: When I register as a single user with an email address, I can not register again as a single user with the same email. However, I noticed that I can register again with the group registration with the e-mail address.
Is there any way to disable this? I would like that if someone has registered with an e-mail as a single user, the same e-mail is not accepted in the group registration.
I hope that I have expressed myself reasonably clearly.