Issue Summary

External user SSO verification incorrectly returns the following error message. 

Hmm... We're having trouble logging you in.
This account has been deactivated. Please contact your organization admin.

Steps to Reproduce

1. Setup the following Atlassian Accounts

2. Add externaluser@externaldomain.com as external user to an organization.

3. Setup External User Security with SSO.

4. As the end user

• Access the site/org and login using externaluser@externaldomain.com
• Click on Verify to initate the External User SSO
• Authenticate on the SSO using alias@externaldomain.com

Expected Results

The following error message should be returned.

We don’t recognize the email you’re using.
Your email for logging into Atlassian must match the one used to access content. Try accessing the content again with same email address.

Actual Results

The following error message should be returned

Hmm... We're having trouble logging you in.
This account has been deactivated. Please contact your organization admin.

Workaround

To complete the external user security verification, log in to the third party SSO with an IDP account that returns the matching email address of the logged in external user Atlassian Account.