You may have looked up at the conversations (https://support.google.com/mail/thread/10086372?hl=en and https://support.google.com/mail/forum/AAAAK7un8RUCBdMOdCbyW4/?hl=en&gpf=%23!topic%2Fgmail%2FCBdMOdCbyW4) from Google support and community websites already. There are no recommendations how to get rid of it yet. Most of the time the error would show when Internet browsers are used to read email messages. Regardless of the creator or developer. There is nothing we can do about it for now, really. This is probably a security mechanism to remind Gmail or GSuite email subscribers to not just open an email from anyone. Especially, those unexpected and unsolicited emails even if they appear to be coming from family members, friends, colleagues, suppliers and business partners. We have observed that the "prompt" usually happens to majority of Microsoft-based Exchange email system being used by the sending party. These are legit accounts, we have verified them, and even turned o...