We encountered an issue for contacts receiving our marketing mails in microsoft outlook (browser and app). Despite having all possible settings in hubspot correctly, we are not able to avoid this issue. We already spoke to Hubspot Support.
My concern now is, that more contacts are seeing this message which could account in a lower opening and click rate.
Does anyone have seen similiar issues sending marketing email through hubspot - in outlook or other providers?

Hi @globilars,
Can you confirm that you have fully authenticated your email sending domain? Manage your email authentication
Have you confirmed with a third-party tool like MXtoolbox? https://mxtoolbox.com/
Which information exactly is displayed when you click on “Weitere Informationen”?
Have you tested this inside as well as outside of your company network to check whether this is a setting or warning exclusive to your company environment, set up by your IT?
Overall, HubSpot marketing emails contain tracking links and parameters: Manage marketing email open and click tracking
This tracking will raise some red flags in some email clients, depending on configuration, and with some email service providers. This is, frankly speaking, within the nature of marketing emails that are tracked. You can turn off tracking which might help with warnings – but then you don’t get to analyze certain data.
Best regards!