This may be a bit out of scope but i need to get some clarification regarding DKIM. Let's say I have O365 and DKIM is already configured, I have selector1 and selector2 configured and is working fine.
However, I have another 3rd party solution that is used for mass mailing. For this they want to use their own DKIM as well.
I would like to know what I should do here?
Appreciate your help on this :)