Issue Summary

When inviting a customer in the Invite Customer dialog, if the email address belongs to a user who already exists but has had their access to the site revoked (making them inactive), then an error message appears. However, the error in the UI does not match the error response for the validation call in the Network console.

Steps to Reproduce

1. Create a user (Atlassian account or Customer account) on a site
2. Go to Site Administration, find the user, and revoke access
3. Go to a Jira Service Desk Project > Customers tab in the project
4. Click Invite Customers to open the dialog
5. Type the email address of the user in steps 1+2 and click enter

Expected Results

The user appears in the dialog with an error. Clicking on the red cross icon shows an error message saying the user is inactive and must be activated before they can be invited as a customer on the project.

Actual Results

The user appears in the dialog with an error. Clicking on the red cross icon shows an error message saying "<email> is not a valid email address". This is misleading and confusing for users.

Workaround

Users could open the Network tab and inspect the response to confirm that the reason the user cannot be invited is because they are inactive