"Email set to ignored because of disallowed from address, email_address_filter_reason = Illegal address" error string from inbound emailIssue Inbound emails are ignored due to error string:Email set to ignored because of disallowed from address, email_address_filter_reason = Illegal addressReleaseAll EnvironmentsCauseFirst Cause:Validate if the received email meets any of the current email filter conditions:How to use Email Address filters to ignore any email from any sender?Email Filters Second Cause:This is most likely due to the FROM sender having a non RFC complaint address, for the RFC please see here:RFC5322For example: There is a phone number listed, without a domain or the structure of the from address is non RFC compliant.Another great example is here:https://learn.microsoft.com/en-us/skypeforbusiness/troubleshoot/hybrid-phone-system/voicemails-not-deliveredUnder: Third Party Email Systems "The primary issue that affects third-party email systems is that the FROM address is formatted for PSTN calls in a non–RFC-compliant manner."The notation is recognizing the FROM address is non-RFC compliant.ResolutionFirst Cause:Remove the condition preventing the email to pass the email filter:How to use Email Address filters to ignore any email from any sender?Email FiltersSecond Cause:The sender must maintain RFC compliance for the inbound email to be received. RFC5322Related LinksInternet Message Format:RFC5322 Email Filters:How to use Email Address filters to ignore any email from any sender?Email Filters