How to remove the unverified sender message?

This is so insane. Someone from my Microsoft family shared a folder with me. They did it from their Microsoft account on an Edge browser. The notification I got in my outlook had the label "unverified sender". How is this possible? Doesn't MS Outlook see that it's from another microsoft account? It's not from an email address with which the other microsoft account was created, it's from the OneDrive system. It feels like I'm in a lame horror "The call is coming from inside the house".

UNHELPFUL TO ME....I have no idea what your instructions are saying. I just need to find the "verify" button

Hi,

I keep getting an 'unverified sender' message in Outlook (desktop and web app). I've added the address to 'trusted sender' and I've whitelisted the domain but still keep getting it.

The sender is 'trusted' and a reputable domain.

Is there anything else I can do on my side or is it down to the sender?

Many thanks,

Charlie

@Microsoft, this is a poor choice, please make some sort of "trust this sender" button. You can even have a pop-up confirmation. But to ask someone else to change their mail configuration? Really? I thought y'all would have a better answer than that.

Oh holy ____. When every other service can make the distinction between listed safe email and junk without having to jump through the hoops Outlook puts forward, when Outlook will distribute email from the very same sender to junk sometimes and my inbox other times...

When Outlook will function as intended for days at a time, then not filter at all...

Yeah sure. The problem lies with me not scrutinizing the sender’s domain, insuring that it has proper SPF, DKIM, and DMARC records set up...

Hilarious.

It would be very helpful if Outlook reported why it classified the email as "unverified" - I understand it could be one of four (or more) things: SPF, DKIM, DMARC, or Outlook's own classification. Without knowing which of these is causing the issue, it is difficult to know how to resolve.

Russel