By default, if we detect an office 365 mail server, we automatically use our email address as the sender. This is to avoid the messages coming to you having a warning about spoofing. If you would still like us to continue to use your email address, you can add a TXT record of “_betterimpact-dont-rewrite-sender” to your mail server to let us know.
A TXT record cannot be used if a DMARC policy is in place.