Hi@Mark_Brailsford,
We're experiencing the same exact issue where the Marketo link suddenly goes to a 404 page but the SFDC link still works. I know it's been awhile but did you e...
Ever since Adobe acquired Marketo, they've been increasingly difficult to work with. It feels like they are trying harder than ever to squeeze every possible penny out of their cus...
I'm not familiar with the Email Deliverability PowerPackbut try checking your SPF record on a website like this one:https://mxtoolbox.com/spf.aspxIt should tell you WHY your record...