Notification mails filed under Spam

Hello Kevin, the notification emails always land in my spam folder. The main reason is the HTML content type which raises the spam score, e.g.:

1.1 MIME_HTML_ONLY BODY: Message only has text/html MIME parts
0.6 HTML_MIME_NO_HTML_TAG HTML-only message, but there is no HTML tag
2.0 TO_NO_BRKTS_HTML_ONLY To: lacks brackets and HTML only

Since the notification mail contains only a few sentences why not keep the content type as default plain text? There are fine possibilities to format plain text.

https://ww.wp.xz.cn/plugins/testimonial-basics/