Cannot run/preview qml files from qtcreator, but works from terminal

phoneticallySAARTHaK

Hi, I recently started learning qt, from the book packt: Application development using Qt creator

I made the hello world project as described in the book.
(Qt quick project > added qt quick UI file) The project builds but doesnt run, or preview
However, explicitly running $ qml6 *qml from the terminal in the project directory does show the preview, and the application window works fine (turns blue)

Running gives this error:

02:09:53: /home/sarthak/git/Qt-learning/app-dev-qtcreator/build-HelloWorldQuick-Desktop-Debug/HelloWorldQuick exited with code 255

and QML preview from build file menu gives: (under General Messages)

Error loading QML Live Preview:
qrc:/HelloWorldQuick/main.qml:9 MyGuiForm is not a type

Same error occurs if I manually run qmake6, make and the binary file.

My main.qml file is:

import QtQuick

Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    MyGuiForm {
        anchors.fill: parent
        mouseArea.onClicked: {
            rectangle.color = "blue";
        }
    }
}

MyGui.qml:

import QtQuick 2.4

MyGuiForm {

}

MyGuiForm.ui.qml:

import QtQuick 2.4

Item {
    width: 400
    height: 400
    property alias rectangle: rectangle
    property alias mouseArea: mouseArea

    Rectangle {
        id: rectangle
        color: "#b00003"
        anchors.fill: parent

        MouseArea {
            id: mouseArea
            anchors.fill: parent
        }
    }
}

.pro and main.cpp files are the default ones.

I downloaded qt6-base, qtcreator(6.0) and qt6-declarative from arch linux repositories. This makes the binaries end with "6". eg qml6, qmake6. Could it be related to this?