outlook inbound email issues?

[nanog <nanog () wjp net>]

I have a client who is receiving 50% of their mail on outlook servers 
for the past few hours.

MX records point to:
xxxxx-com.mail.protection.outlook.com has address 104.47.38.36
xxxxx-com.mail.protection.outlook.com has address 104.47.36.36

Anyone aware of outlook issues or have someone they can poke to check 
into this?  (Both answer smtp requests, guessing a queue is backed up 
somewhere.)

thanks
bill

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