<!--This template is a great use for issues that are feature::additions or technical tasks for larger issues.--> ### Proposal <!--Use this section to explain the feature and how it will work. It can be helpful to add technical details, design proposals, and links to related epics or issues.--> <!--Consider adding related issues and epics to this issue. You can also reference the Feature Proposal Template (https://gitlab.com/gitlab-org/gitlab/-/blob/master/.gitlab/issue_templates/Feature%20proposal%20-%20detailed.md) for additional details to consider adding to this issue. Additionally, as a data oriented organization, when your feature exits planning breakdown, consider adding the `What does success look like, and how can we measure that?` section.--> <!--Label reminders Use the following resources to find the appropriate labels: - Use only one tier label choosing the lowest tier this is intended for - https://gitlab.com/gitlab-org/gitlab/-/labels - https://about.gitlab.com/handbook/product/categories/features/--> When a user tries to setup Slack integration on a new project and another project was already setup with that alias name, the integration fails and the UI shows 422 error - `422: The change you requested was rejected` This is not clear to the user why the failure occured. Backend Rails will show the exception as: `"exception.message": "Validation failed: Alias This alias has already been taken"` This gives a better idea that the alias name should be changed. We should make this clear in place of the 422 error.