Not able to add a previously bounced email into a list

Hello,

I try to add an email in a list of a client. I can't. I found in the database this email in an other list in an other client.

I think you check in all the database (multiple clients) if the emails is right, and if it's bounce (it can be bounce temporary...) for exemple, we cannot add the email in a list.

Can you verify?

Thanks,

best regards,
Lucas