Unexpected HTTP response: 500

Request
{
    "address" => [
        ("subsystem" => "messaging-activemq"),
        ("server" => "default"),
        ("bridge" => "qux")
    ],
    "operation" => "write-attribute",
    "name" => "credential-reference",
    "value" => {"clear-text" => "ghjkghkj"}
}

Response

Internal Server Error
{
    "outcome" => "failed",
    "failure-description" => "WFLYMSGAMQ0019: Alternative attribute of (credential-reference) is already defined.",
    "rolled-back" => true,
    "response-headers" => {"process-state" => "reload-required"}
}