Are you still having this issue? I have intermittent “Could not read from smtp.office365.com” issues, but the vast majority are going through. We are below the O365 limit of 30 per minute and 10,000 per day. Unable to find the same situation in the knowledgebase, or any responses to a similar situation.
I’ve having this same issue with smtp.Office365.com. Very small percentage, but critical emails are not being sent. Has a solution been found?
