When an administrator tries to add someone as a Team Account using an email address that already exists under a different role in the same project, the system shows a generic error that does not explain the specific cause.

Update the error shown when a Team Account email already exists under another role so it states the specific cause (e.g., that the email is currently registered as a Reader) and points to the appropriate next step, such as converting the existing account.

Benefit:Administrators can immediately understand why an email address was rejected and resolve the conflict on the first attempt, without needing to guess at the cause or try multiple approaches.