How to delete the email address of the admin?

I’ve been trying for quite a while now to change the admin email address of my account from info@... to timo@... and to delete info@... after that because I want to make a group that is reachable under that address .

I already made timo@... the primary e-mail address, but when I try to delete info@... a message pops up telling me to contact the administrator, although this is who I am.

How can this be done?

I’d appreciate any help. Thank you!