Ask HN: Are certain ccTLD emails sent to blackholes?

I've been using my a ccTLD (.PW) for many years, but it seems like it's somehow ended up on a blacklist of sort and certain companies will either reject it (e.g. comcast.net) or it will never receive it (e.g. statefarm.com, metlife.com). After about three weeks of back-and-forth with the Comcast senior tech, they found there was a "domain block" -- which they kindly removed and the issue resolved. I've not been able to find the right person at statefarm or metlife to contact, and I worry there could be other companies they may silently reject emails. I have DKIM and SPF correctly setup, and I've checked all the blacklists and I'm not on any of them. Emails are sent via FastMail, and my other domains don't have this problem (but they're all 'normal' TLDs). Is this a specific problem with certain ccTLDs? Would switching to a different ccTLD solve the problem, or would I really need to switch to a 'normal' TLD?