primary address change

primary address change

Hi

I just set up this account and verified my domain and added info@insiderinteract.com. I want to change "info" to "support"  (support@insiderinteract.com) .

I tried to add another mail account but it requires server address in setup process which I don't know from where to get.
also tried to Add Email Address in Account > Email Address but it sends OTP first but I haven't made support@insiderinteract.com anywhere so how is it possible to get this OTP?

Kindly let me know how to solve this issue.

Thanks