There is a definite 5 minute +/- delay in emails sent from our ESP8266 devices to Office 365.
Emails sent from any mail client like Opera mail, Yahoo mail, Outlook.com, webmail(using same email as ESP8266) are delivered to Office 365 in 2-3 Seconds.
Emails sent from the ESP8266 to webmail, Opera mail clients, etc. are delivered in a few seconds.
I have each of the ESP8266 email sending addresses added to the Office 365 Safe Senders list.
Has anyone else experienced this?
Is this a known issue?