Hi bucket-o-rust,
We will be happy to assist you with your concern in receiving an email from that third party domain.
A possible reason why you’re not getting an email from that person is it might be their domain is blocking your Hotmail account. There might be some rules and filter on your Hotmail account that we need to check.
Make sure that on your mailbox it was set to “View All” for us to check all emails on your Inbox. Please check these settings on your Hotmail account like the junk mail folder, email rules. Please refer to this article below for additional references.
I am not receiving Email sent by friends/family
However, if after checking the article above we still not able to get that email I advise you to contact that person in another way and inform them to get in touch to their domain administrator so that they can check or configure some settings in there end.
Feel free to reply back to this post.
Thanks.