Use the the same email address for MYOB 2FA as you use for your MYOB Acumatica user profile.
So you can authenticate, it also needs to be a unique email address that you have access to – normally just your own work email address. It can’t be a shared inbox email address or someone else’s email address.
If you’re not sure about what email address you should use, check with your manager or your MYOB Acumatica site administrator.