What does the error "This email address is already used by..." mean?

Question

What does the error "This email address is already used by [user]." mean?

Answer

An email address cannot be used both as a support address and as an identity for an agent or end user. To use the email address as a support address, you must detach it from the user it is currently associated with. 

Steps to resolve

First, determine where that email is already in use. 

1. Click the magnifying glass icon in the upper right corner and search for the email address in question.
2. On the search results page, click Users.
3. Click on the user/email, which will bring you to the profile page for that user.
4. Choose one of the following actions:

• Change the email address associated with this user to another address. If this is a legitimate user, make sure to use a valid email address they can receive an email at.
• Or, delete the user. If the user exists for testing purposes or is otherwise not a legitimate end user or agent, you can simply remove their profile, freeing up the email address in question. 

Once you have updated or removed the user, you can use the email address as a support address. Return to Admin > Channels > Email to add the support address.