It gets weirder yet..
I also tested by sending myself an email by another address (not Hotmail) and it got refused by Hotmail. Either with or without attachments. BUT since it is also pop-ed to Hotmail it DOES send the Postmastersemmage that was sent to the senders address (it was popped right?) that the original message was refused (...)

It opens the inbox but can open the mail BUT not the contents... and can't open the folders apart from the INBOX.
Form the inbox stragely enough you can delete but not open deleted mails-folder
I tried to see if the link
https://portal.office.com/BoxError.aspx?aspxerrorpath=/ServiceStatus.
would work but also this has a error message
Endless waiting to send a message from Hotmail cot my own address whcih is popped to my Hotmail.
However: strangely enough I CAN download the attachments of previous messages (by clicking in the inbox on the attachment) but not open the message itself.. huh ?

¿ and of course
https://portal.office.com/ServiceStatus
shows all is peachy.. well.. Not...