[BUG] Internal error code exposed when email or username already exists during user creation

[debosmita-S]

Description:

When creating a new user from the Admin panel, Rocket.Chat shows an internal error key ([error-field-unavailable]) instead of a user-friendly message if the email or username already exists.

This exposes an internal error identifier to the UI and causes confusion for administrators.

Steps to reproduce:

1. Go to 'Administration → Users'
2. Click on 'New user'
3. Enter an email address that already exists
4. OR enter a username that already exists
5. Submit the form

Expected behavior:

A clear, human-readable validation message should be shown, for example:

• “Email address already exists”
• “Username already exists”

Actual behavior:

The UI displays an internal error message such as:

miraS is already in use :( [error-field-unavailable]
mirasen@gmail.com is already in use :( [error-field-unavailable]

(See attached screenshots)

Server Setup Information:

• Version of Rocket.Chat Server: latest (Docker)
• License Type: Starter
• Number of Users: 2
• Operating System: Windows
• Deployment Method: Docker Compose
• Number of Running Instances: 1
• DB Replicaset Oplog: Enabled (default docker setup)
• NodeJS Version: Bundled with Docker image
• MongoDB Version: Docker image default

Client Setup Information

• Desktop App or Browser Version: Chrome (latest)
• Operating System: Windows

Additional context

This appears to be an error-mapping or UI validation issue where backend error identifiers are directly surfaced in the UI instead of translated messages.

This impacts admin UX during user creation.

Relevant logs:

No crash logs observed.
Issue appears to be related to frontend error handling / message mapping.

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[SuyashJain17]

I can reproduce this issue where the internal error key is shown instead of a user-friendly validation message during admin user creation.
I’d like to work on improving the error mapping so clear messages are shown for duplicate email or username. Please let me know if I can proceed.

[Ch-saketh]

Hi! 👋 I’d like to work on this issue.

From my understanding, the error message shown when a user tries to sign up with an existing email or username exposes an internal error code rather than a proper validation message. A good UX should show a clear, user-friendly error instead of an internal exception.

Proposed approach:

Modify the frontend signup handler to catch the validation error response from the backend.

Update the API response parsing logic to check for error.errorType === 'duplicate_key' (or the relevant error code name in the Rocket.Chat API response).

Replace the default message with a clear user message such as:

“A user with this username or email already exists. Please choose a different one.”

Ensure the changed message is displayed on the UI component where the user submits the signup form.

Add a small UI test case (snapshot or unit test) for the new warning message.

Here is a possible condition snippet (example):

if (error.errorType === 'duplicate_key') {
setFormError('username', 'A user with this username or email already exists.');
} else {
setFormError('username', error.message);
}

I’m happy to work on this and submit a PR once confirmed. Thanks! 😊

[debosmita-S]

Thanks everyone for the interest!

I’ve already reproduced this issue locally and shared screenshots.
I’m currently working on a fix and will open a PR soon.

[Rohit-Rathod95]

Hi, here’s the approach I’m planning to take for this issue:

Problem:
Currently, when creating a user with an existing email or username, the UI directly displays the backend error identifier (error-field-unavailable). This exposes internal error keys and results in a confusing experience for administrators.

Approach:
I plan to fix this entirely on the frontend without changing backend behavior:
Intercept the error response returned from the user creation API.
Detect the error-field-unavailable error code.
Map this backend error to clear, human-readable validation messages depending on the field:
Email → “Email address already exists”
Username → “Username already exists”
Use the existing i18n/translation system instead of hardcoding strings.
Display the mapped message in the UI (inline validation / toast), following existing patterns.

Why this approach:
Keeps backend logic unchanged
Prevents exposing internal error identifiers
Improves admin UX
Maintains backward compatibility and localization support

Please let me know if this approach looks good before I start implementing it. Thanks!

[debosmita-S]

Hi @Rohit-Rathod95 , thanks for the interest!

I’ve already reproduced this issue locally and shared screenshots.
I’m currently working on a fix and will open a PR soon.

[Rohit-Rathod95]

Hi @Rohit-Rathod95 , thanks for the interest!

I’ve already reproduced this issue locally and shared screenshots. I’m currently working on a fix and will open a PR soon.

Thanks for the update!
I appreciate you taking this up. I’ll follow the PR to understand the fix and learn from it.
Looking forward to contributing to other issues in the project.