It breaks forwarding services that don't use SRS [1], for example OVH's. Like you mention, the next hop (example: gmail) will see it coming from the redirecting

It breaks forwarding services that don't use SRS [1], for example OVH's. Like you mention, the next hop (example: gmail) will see it coming from the redirecting domain which is not valid per SRF rules. A SOFTFAIL will send a lot of emails to spam, a HARDFAIL means the email might be rejected outright. [1]: https://en.wikipedia.org/wiki/Sender_Rewriting_Scheme https://en.wikipedia.org/wiki/Sender_Rewriting_Scheme I need to move my domains off of OVH...