I have a strange situation where an email address contains an authentication key for an SMS provider. It leaves our system with a capital A, Sophos processes the email and then it returns it to O365 with a lowercase A which causes authentication to fail. If I edit the outbound Sophos rule to add an exception for emails sent to that destination domain, it works perfectly fine and goes out with a capital A.
Why would Sophos be altering a destination address and changing the case?
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