Does anyone run into problem with their custom domain's emails being sent to other people's spam folders?

Almost everyone does.

No, although I don’t host my own email so my “reputation” is bound to my email provider (soverin.net). I’ve found https://mxtoolbox.com/SuperTool.aspx to be useful when checking email sending at work, though

Depending on how the hosting provider sets things up, you might have to create a few dns entries (spf, dkim, dmarc) to help your reputation. Also avoid using addresses historically reserved for admin stuff, like admin, mail, etc.

You need a DMARC policy, and then dkim or and spf record set up. Without these a lot of email providers will just assume your emails are spam.

https://kb.mailbox.org/en/private/custom-domains/spf-dkim-and-dmarc/

Thats not true at all

+1 for Soverin. They are a great provider. I have 4 domains and a dozen mailboxes with them.

Is there a way to do this without signing up for another subscription?

A domain? No. You'll have to pay for your domain as long as you want to keep it. They're not very expensive though. A basic .com will usually run you about 10–15 dollars per year.

Even then, a lot of email is reputation based on ip blocks. You can have all of those things correct and still be sent to spam if you’re using a cloud provider or the like. If you want to avoid trying to get up reputation up, your best bet is to use a reputable mail sending system like resend or smtp2go

I wasn’t even thinking about self hosted email, but you’re right about that.

Yes, but you'll have to use an alternative DNS system that very few people use.

You can run email on a custom domain, but as other replies demonstrate, it's a huge challenge these days. (My primary email is on a custom domain, but I probably wouldn't do it again if I hadn't already been on it for two decades.)

Yep, the big ones (MS, Google) don't give a shit about your self hosted e-mail server and throw all of your mail to spam. They don't do that with replies though.

Pretty much every company in the world runs their email on a custom domain. I really doubt the domain is the problem.

I've hosted websites since 1997, and for the last decade, I've given up fighting just that. I use - and this is not an ad, but is an endorsement - mxroute to handle that. They handle fighting blacklists so I don't have to worry about it.

Glad to explain more if wanted, but it's pretty simple to set up - as long as you control your DNS.

Exactly. I can understand the push to discourage the general public from hosting their own emails but serving up emails on a custom domain (including self hosting) is not as difficult as it's made out to be. It just takes some patience if the right DNS entries are in place.

Set your DMARC and SPF

Are you referring to running your own email servers specifically?
If so then I agree it’s probably not worth the trouble.
Email service is inexpensive with large providers and deliverability is good also with customer domains.

I would but the registrars want you to provide personal info. It's not PII but it can be traced back to your real identity and I can't have that.

Out of curiosity, which system?

As long as your DKIM and SPF are correctly configured in your DNS (usually your registrar) and the IP of the email server is not blacklisted by some others, you should be just fine.

In that case, something like njal.la is probably your best bet.

https://opennic.org/ is probably the only viable system right now. The others are run by Russia, China, or crypto bros.

I'll check it out, TY

I recently swapped to a custom domain with PurelyMail as the backing and sometimes it doesn't even go to spam but straight to the void. I had to add it to my work Outlook's trusted list for it to even show up at all. Also signing up for store rewards the other day the system wouldn't even recognise my address as valid. That said, all my emails to businesses have been responded to as normal so I have yet to have major issues.