New marketing email marked as unverifiable when sent to leads

I’ve sent several marketing emails through HubSpot to my clients. However, despite the fact that they are receiving the emails, a message stating ‘The identity of this sender has not been verified’ appears. I’ve communicated with these clients via email through HubSpot in the past, so this is not the first interaction. Could you please advise on how to address this issue of unverified sender identity?

Hi @PGarg4,

Where exactly does this message appear?

It appears on the receiver’s email. I’ve attached a screenshot of what my leads see when they receive the marketing email from husbpot.

Hi @PGarg4, I’m not seeing a screenshot (?)

I’ve attached it to this email. let me know if you can see it now