The most common problem is that you will have used this e-mail address to register you as an Agent.
This e-mail address will now control your Branches and Users.
Of course there will be occasions where you are the branch and the user, and we suggest for your username you just use firstname.lastname@company.com and keep this format for any other users who may use OnBoard Pro.
For example
John Smith of Riverside Lettings (john@riversidelettings.com) has registered this e-mail to create Branch details and User details. John is unable to use this e-mail as a user so creates john.smith@riversidelettings.com or could use j.smith@riversidelettings.com.
You could also make it simple and create all your users in the format of firstname.surname@username.com it's entirely up to you.