troubleshooting emails not received

[mrstrong]

Hi,

 

we are using Office 365 and I've had reports from a user trying to send emails all week to an external email address

but they are not receiving them.

 

Strange thing is they able to email our user and apparently yesterday our user's reply worked but today it didn't.

 

Any ideas/tips how to troubleshoot this? E.g anywhere I can look in admin centres to check if email got sent

or turn on "verbose logging" for this user to trace stuff ? Not sure if this is even possible with email?

[Andycat]

Message trace in Admin cetre