WordPress has a built-in feature that detects when a plugin or theme causes a fatal error on your site, and notifies you with this automated email.
In this case, WordPress caught an error with one of your plugins, Graphina - Elementor Charts and Graphs.
Error Details
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An error of type E_PARSE was caused in line 31 of the file /var/www/html/wp-content/plugins/graphina-elementor-charts-and-graphs/utils/graphina_chart_helper.php. Error message: syntax error, unexpected ‘|’, expecting ‘{’