Hey @JustJassy 

Thank you for asking the Klaviyo Community for insight! Happy to help with your test email showing the spam banner! 

There a a number of reasons why Gmail could mark your test email with the banner. It can depend on how many test emails you have sent, the senders address/reply-to issues or corporate spam filters and firewalls. Why Some Preview Emails Go to Spam goes in depth on this and will help provide insight on why this can happen. It also provides some workarounds like using the template editor to preview your emails. @david.to provided a number of resources around emails being sent to spam inbox and what you can do to mitigate the challenge if it is not just your test emails being delivered with the spam banner in this Community post:

I hope that the Help Center article and the Community post provide the insight you are looking for around the spam banner. We truly appreciate you and your engagement with the Klaviyo Community! 

Thank you for being a member!