Unable to send email from mac outlook to onenote?

The first thing I would do is check to see if Microsoft has issued updates for the applications in question. If they have not, I'd consider uninstalling and re-installing them. If that doesn't help, contact Microsoft for further assistance with their products. Given that you are also seeing the same problem when you are using Microsoft's web interface, it sounds as if it is their problem.

Can iOS sandboxing be toggled?

iOS is the operating system for iPhones. You did not indicate that you were using an iPhone. Are you? If so, how does it figure in this problem?

Macs run on macOS. It does not use the same type of sandboxing as iOS.

Was there ever a resolution to this? I am receiving it now

¿Having problems with two Microsoft products that won't talk to each other?

I can recommend some good Apple replacement products that are not so troublesome.

Otherwise, contact Microsoft support.

Getting similar message:

Error: "an unexpected host was loaded when attempting to perform silent auth: DOMException was thrown: 'SecurityError: Blocked a frame with origin \"https://www.onenote.com\" from accessing a cross-origin frame. Protocols, domains, and ports must match.'"

i have spent over 6 hours with Microsoft support including clearing everything out on MacBook. Same issue on iPhone and iPad. Microsoft support tier 2 supposed to contact me tomorrow… help!

I am also receiving this exact error.

Gronne wrote:

I am also receiving this exact error.

Then my advice is the same. See my Apple recommended post above.