We've successfully setup Mailflow for our MS365 domain. We used the "copy existing MS365 Domains and Policies" and confirmed.
Mailflow seems to be working correctly after testing. All looking good. However I am curious what to do with the existing DNS settings that we've configured at our 3rd party DNS hosting for the old situation.
What happens to existing created records that are still pointing to the SOphos Hydra servers?
DO these servers need to be removed and MX reverted back to the initlal MS365 DNS from Microsoft?
I have a hard time finding out if anything in DNS config is neccesary to revert or not.
DNS MX records should all point to M365 and SPF should be updated as well to v=spf1 include:spf.protection.outlook.com -all and of course any other records you need in your specific SPF record.
In what way Doug, Sorry I was out on PTO and business travel the last couple weeks. You should always create a support case if you need immediate response. In the UI you should have seen an X (all the way to the right) where you could delete the connection vs just disconnecting. It would not be under Mail Flow but under Settings > Domain Settings/status, those are the connections to remove IF you have Mailflow working correctly.