Email addresses must be unique across accounts
An email address that is invited must be unique across Circle accounts. If you invite an email used on another developer or Circle Mint account the user will not be able to successfully join your team.A common workaround to this issue is resolved by using plus addressing. To do this, append a plus ("+") sign and any combination of words or numbers after your email address For example, if my email were [email protected] I would use the email address [email protected], and I would still receive emails to my original email account. Google Workspace and Microsoft 365 support plus addressing. If you do not use one of these providers, please check with your email hosting provider before using it.