> Actually I initially got placed in spam too in Gmail/Outlook but I always replied to my own emails and marked them as "Not Spam" and the problem just kinda disappeared?

Did you continue to use those same Gmail/Outlook accounts for your deliverability testing? Because that would explain why you're not encountering any deliverability issues in your testing.

Try to create fresh Gmail and Outlook accounts and see if you can actually deliver to them.

I have multiple Gmail accounts (like 5+ lol) as well as my own Google Workspace account (for unlimited GDrive) so for deliverability to Gmail testing I just used that.

I had a couple Hotmail/Microsoft Live/Outlook accounts too.

But deliverability for me was always quite consistent. If it went to spam on one account, it would go to spam on all of them.

At this point I no longer do deliverability testing because I simply don't see the need to. No one has ever complained about my emails going to spam so the thought has never really crossed my mind.

I've also had a lot of trouble creating Outlook accounts for some reason. New accounts seem to get suspended real quick. My previous Outlook accounts have mostly all been suspended too. Not sure what's going on there...

EDIT: From the output of `dig` I can see my landlord uses Outlook. I just emailed him a couple days ago and he replied so I guess all is well?

> But deliverability for me was always quite consistent. If it went to spam on one account, it would go to spam on all of them.

You mentioned that your emails on Gmail and Outlook initially went to spam, but that you clicked "not spam" on those emails. This action should prevent your emails being flagged as spam for that particular receiver who clicked not spam. Obviously it can't work such that one person clicks "not spam" on an email, and then everything from that sender is whitelisted for everybody. Because then the spammers could just register a single email account, click "not spam" once, and then spam everybody. So my point is, if you test deliverability on email accounts where you have already whitelisted the sender, of course it's going to look like email is delivered.

> I just emailed him a couple days ago and he replied so I guess all is well?

Presumably you and your landlord have already emailed each other in the past, so any anti spam system should allow emails between those addresses to reach their destinations. It doesn't really prove anything.

> You mentioned that your emails on Gmail and Outlook initially went to spam, but that you clicked "not spam" on those emails. This action should prevent your emails being flagged as spam for that particular receiver who clicked not spam. Obviously it can't work such that one person clicks "not spam" on an email, and then everything from that sender is whitelisted for everybody. Because then the spammers could just register a single email account, click "not spam" once, and then spam everybody. So my point is, if you test deliverability on email accounts where you have already whitelisted the sender, of course it's going to look like email is delivered.

Obviously I'm aware that me clicking "Not Spam" would not instantly whitelist me in Microsoft's systems, but the hope is that it would influence the spam algorithm somewhat. It doesn't even whitelist me on that account because even after clicking "Not Spam", my emails still went to spam for some time.

> Presumably you and your landlord have already emailed each other in the past, so any anti spam system should allow emails between those addresses to reach their destinations.

Maybe, but my entire university runs on Office365 and I never had any trouble sending to friends and professors there (who have never sent me emails previously).

I'm not really sure what you are trying to say here? Should I have some sort of commercial deliverability monitoring system setup? Do you have insights into what "real email providers" use?

I guess I'm mainly trying to point out how difficult it is to estimate deliverability. So, rather than pointing to a solution, I'm merely trying to illustrate that the problem exists. There's so many people in this thread claiming that measuring deliverability is "trivial" or getting deliverability is easy ("just do X,Y, and Z"). And when you get down to it, it's mostly people saying "I sent an email to myself and it went through" or saying "nobody ever emailed me back saying they didn't get my email", and so I'm poking holes at those anecdotes. No larger point behind any of this.

Or, if I were to put a larger point behind it, I would say that getting good deliverability is hard and it doesn't make sense to try it unless you are delivering email on behalf of a large amount of people (rather than merely yourself).