GMail is being flaky as hell about accepting or not accepting email from the RW server, 173.255.233.133 - sometimes works, sometimes hits spam, sometimes gets 550 refused (with no particular reason given). Google doesn't do customer service, of course.
We don't *seem* to be in the email blackhole lists (I see our IP 173.255.233.133 gets 6 DNSBL hits in http://www.kloth.net/services/dnsbl.php but I go to the sites in question and they say it's not listed); so the only other hypothesis that springs to mind is that they don't like email coming from J. Random Linode VM (and at least one DNSBL does consider that a reason). Has SPF/DMARC helped anyone with this sort of thing?
What does one do in this case? Is there e.g. a commercial third-party email relay service that, say, GMail users will get mail from?
- d.