hopefully this is a simple question to answer...
For the last few years I've had only SPF setup with our O365 Exchange Online domain's DNS records. I haven't yet setup a DKIM because we've never really had any issues with spam classification or NDRs. But now that we've started to do some email marketing for the company and are looking at sending out a few thousand emails via ActiveCampaing, I think we need to add a DKIM.
If I add the ActiveCampaign generated DKIM for our naked domain (the one hosted on O365) but not an O365 recommended DKIM (yet), will this individual DKIM have any negative effect on legitimate outbound emails from our staff?
Yes, I know that I can have multiple selectors in one DKIM to authorise a bunch of sending services and should implement this, but I don't yet know how to do it, so for the moment I'm specifically asking about the single selector DKIM for ActiveCampaign even if it's temporary for the first day or so of this email marketing blast.