Checkbox with Thymeleaf - SpringInputCheckboxFieldTagProcessor

I am trying to add a checkbox to my form. While I am creating a user, the checkbox works fine. However, while I am editing a user, I get this error.

Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputCheckboxFieldTagProcessor'

And here is the code: Error is this line - <input type="checkbox" th:field="*{isEnabled}" checked/>

                                <div class="form-group row">
                                    <label class="col-sm-2 form-control-label">Enable User</label>
                                    <div class="col-sm-10">
                                        <input type="checkbox" th:field="*{isEnabled}" checked/>
                                    </div>
                                    <label class="col-sm-2 form-control-label">Lock User</label>
                                    <div class="col-sm-10">
                                        <input type="checkbox" th:field="*{isLocked}" checked/>
                                    </div>
                                </div>

What could be an issue here.