Remove default liferay error message from portlet

 Add following in your action method


PortletConfig portletConfig = (PortletConfig)request.getAttribute(JavaConstants.JAVAX_PORTLET_CONFIG);
        LiferayPortletConfig liferayPortletConfig = (LiferayPortletConfig) portletConfig;
        SessionMessages.add(request, liferayPortletConfig.getPortletId() + SessionMessages.KEY_SUFFIX_HIDE_DEFAULT_ERROR_MESSAGE);