Don't allow the creation of user with same Email id in the same domain

ISSUE TYPE

Enhancement/Improvement Request

COMPONENT NAME

Component: API/ UI

CLOUDSTACK VERSION

Cloudstack version 4.18

SUMMARY

Don't allow the creation of user with same Email id in the same domain

Steps to reproduce the issue

1. Navigate to domain > Accounts > Click on a particular Account > Create say user1 with (test@gmail.com)

2. Navigate to domain >Accounts > Click on a particular Account > Create say user2 with (test@gmail.com)

Screenshot

**Expected behaviour**

Cloudstack should not allow to create the user with same Email address in the same domain

If a oauth is configured for a user in a cloudstack , email address is used as key to identify.

Cloudstack throws an error saying there is an already multiple user having the same email address in the same domain.

It would be proactive checking if we could block the creation of user with same email address during the user creation

The issue names API/UI user creation as the entry point but provides no implementation files or tests. Trace creation for users within a domain, then add a regression test showing that a duplicate email is rejected in the same domain while the expected behavior remains verified.

Written by the indexing model from the issue text.