WHMCS AddClient API Returning Null on Success

[lindiarm]

Issue Description:

We are using the AddClient API from WHMCS, which has been working as expected until recently. We encountered an issue where, after the action is executed successfully, the API returns null in the response instead of the expected result.

Code Implementation:

AddClient Action:

class AddClient extends Action implements ActionInterface
{
    public function handle($data = [])
    {
        $params = array_merge([
            'action' => 'AddClient',
        ], $data);

        return Whmcs::getClient($params)->json();
    }
}

AddClientRequest Validation Rules:

public function rules()
{
    return [
        'firstname' => 'required|string|max:255',
        'lastname' => 'required|string',
        'email' => 'required|string|email|max:255',
        'phonenumber' => 'required|string',
        'companyname' => 'nullable|string',
        'address1' => 'required|string',
        'address2' => 'nullable|string',
        'city' => 'required|string',
        'state' => 'required|string',
        'postcode' => 'required|string',
        'country' => 'required|string|max:2',
        'marketingoptin' => 'nullable|boolean',
        'password2' => ['required', 'confirmed', Rules\Password::defaults()],
        'consent' => 'required|boolean|accepted',
    ];
}

Problem:

Upon calling the AddClient action, the API returns null in the response, even though the user and client accounts are successfully created in the database. The expected output should be:

{
    "result": "success",
    "clientid": "1"
}

However, it currently returns null while still saving the client and user data in the system.

Store Method Implementation:

public function store(AddClientRequest $request)
{
    $data = AddClient::run($request->validated());

    if ($data['result'] === 'error') {
        return back()->with('error', $data['message']);
    }

    // Other logic if success...
}