WP RSS Aggregator Error

<b>WP RSS Aggregator</b> has encountered a critical error. The safest course of action is to deactivate the plugin and any of its add-ons on this site using the button below. Once you’ve done that, you may reactivate them and start using the plugins again. If the problem persists, please copy the below error and send it to our support team with an explanation of when and how it happened.

Click to show error details
Error Message:
RebelCode\Entities\Properties\Property::getValue(): Argument #1 ($entity) must be of type RebelCode\Entities\Api\EntityInterface, null given, called in /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Entities/Properties/WpraItemSourceProperty.php on line 85 (wp-content/plugins/wp-rss-aggregator/lib/Entities/Properties/Property.php:39)
Stack trace:
#0 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Entities/Properties/WpraItemSourceProperty.php(85): RebelCode\Entities\Properties\Property->getValue()
#1 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/lib/Entities/Entity.php(75): RebelCode\Wpra\Core\Entities\Properties\WpraItemSourceProperty->getValue()
#2 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/lib/Entities/Entity.php(145): RebelCode\Entities\Entity->get()
#3 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Data/EntityDataSet.php(94): RebelCode\Entities\Entity->export()
#4 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Util/IteratorDelegateTrait.php(85): RebelCode\Wpra\Core\Data\EntityDataSet->getIterator()
#5 [internal function]: RebelCode\Wpra\Core\Data\EntityDataSet->rewind()
#6 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Util/IteratorDelegateTrait.php(58): iterator_to_array()
#7 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Util/IteratorDelegateTrait.php(126): RebelCode\Wpra\Core\Data\AbstractDataSet->yieldIterationValue()
#8 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/Environment.php(497) : eval()'d code(63): RebelCode\Wpra\Core\Data\AbstractDataSet->current()
#9 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/Template.php(453): __TwigTemplate_9764ee7ae096758462030ae53fb1d66b89f915c7b48c80ff121165b9eb193206->doDisplay()
#10 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/Template.php(420): Twig\Template->displayWithErrorHandling()
#11 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/Template.php(432): Twig\Template->display()
#12 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/Extension/CoreExtension.php(1607): Twig\Template->render()
#13 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/Environment.php(497) : eval()'d code(43): twig_include()
#14 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/Template.php(453): __TwigTemplate_e1e57bc4eb1a549a4201f37f8ca908098887f5a700f10a797a742faab5d1f81b->doDisplay()
#15 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/Template.php(420): Twig\Template->displayWithErrorHandling()
#16 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/Template.php(432): Twig\Template->display()
#17 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/vendor/twig/twig/src/TemplateWrapper.php(47): Twig\Template->render()
#18 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Templates/TwigTemplate.php(59): Twig\TemplateWrapper->render()
#19 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Templates/Feeds/Types/AbstractFeedTemplateType.php(41): RebelCode\Wpra\Core\Templates\TwigTemplate->render()
#20 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Templates/Feeds/MasterFeedsTemplate.php(172): RebelCode\Wpra\Core\Templates\Feeds\Types\AbstractFeedTemplateType->render()
#21 /homepages/38/d92918850/htdocs/sof/wp-content/plugins/wp-rss-aggregator/src/Handlers/FeedShortcode/FeedsShortcodeHandler.php(48): RebelCode\Wpra\Core\Templates\Feeds\MasterFeedsTemplate->render()
#22 /homepages/38/d92918850/htdocs/sof/wp-includes/shortcodes.php(355): RebelCode\Wpra\Core\Handlers\FeedShortcode\FeedsShortcodeHandler->__invoke()
#23 [internal function]: do_shortcode_tag()
#24 /homepages/38/d92918850/htdocs/sof/wp-includes/shortcodes.php(227): preg_replace_callback()
#25 /homepages/38/d92918850/htdocs/sof/wp-includes/class-wp-hook.php(310): do_shortcode()
#26 /homepages/38/d92918850/htdocs/sof/wp-includes/plugin.php(205): WP_Hook->apply_filters()
#27 /homepages/38/d92918850/htdocs/sof/wp-includes/widgets/class-wp-widget-custom-html.php(148): apply_filters()
#28 /homepages/38/d92918850/htdocs/sof/wp-includes/class-wp-widget.php(394): WP_Widget_Custom_HTML->widget()
#29 /homepages/38/d92918850/htdocs/sof/wp-includes/widgets.php(835): WP_Widget->display_callback()
#30 /homepages/38/d92918850/htdocs/sof/wp-content/themes/colormag/sidebar.php(27): dynamic_sidebar()
#31 /homepages/38/d92918850/htdocs/sof/wp-includes/template.php(783): require_once('/homepages/38/d...')
#32 /homepages/38/d92918850/htdocs/sof/wp-includes/template.php(718): load_template()
#33 /homepages/38/d92918850/htdocs/sof/wp-includes/general-template.php(136): locate_template()
#34 /homepages/38/d92918850/htdocs/sof/wp-content/themes/colormag/inc/helper-functions.php(88): get_sidebar()
#35 /homepages/38/d92918850/htdocs/sof/wp-content/themes/colormag/inc/template-tags.php(222): colormag_get_sidebar()
#36 /homepages/38/d92918850/htdocs/sof/wp-content/themes/colormag/single.php(80): colormag_sidebar_select()
#37 /homepages/38/d92918850/htdocs/sof/wp-includes/template-loader.php(106): include('/homepages/38/d...')
#38 /homepages/38/d92918850/htdocs/sof/wp-blog-header.php(19): require_once('/homepages/38/d...')
#39 /homepages/38/d92918850/htdocs/sof/index.php(17): require('/homepages/38/d...')
#40 {main}