I've seen some good advice there from @leonardo-orihuela-8122 and @mkhuzaima-afzal-6901. Still curious to see if anyone else is dealing with this and fixed it. Maybe hear some strategies from , or whoever is used to deal with this? At this point it looks like a global issue right now. My client campaigns were 100% microsoft inbox rate just weeks ago. Now you won't get over 0% inbox rate even for something as simple as "hey will you be on the meeting tomorrow?" one-line type of emails. Not a copy issue. Tested this as well on other mailboxes i haven't used for months, still warming up daily. 0% outlook. 100% google.
I'm considering buying Outlook mailboxes soon. Though I'm not sure if it will fix anything? Getting more clarity would be great.