Dnia 5.05.2020 o godz. 08:32:43 Michael Orlitzky via mailop pisze: > > That message was never retried, even though this page says you'll retry > for 72 hours: > > https://sendgrid.com/docs/glossary/deferrals/ > > That sample is fresh in my mind, but it's not a unique problem. We do > pre-queue scanning and sometimes you're just gonna get a busy signal. > We'd all love it if you could re-send at least once per the RFC so that > people will stop calling us about lost messages =)
I have also seen previously several times that Sendgrid did not retry. However, I've also seen cases when Sendgrid did retry properly. I wonder if it depends on the sender/customer. Maybe they retry when sending messages for some customers and don't retry when sending for other ones? Personally I had a slightly different problem with Sendgrid Sometimes when they retry, they retry immediately (without any noticeable delay), and each time connect from a different IP address. After only a small number of such unsuccessful retries, they give up. Again, it happens only for particular senders and not for others. Retrying immediately when you get a 4xx makes no sense in my opinion, because if 4xx response is caused by some issue on the receiving end, you couldn't expect that the issue will go away immediately once you retry. Usually it takes some time to resolve the issue, so the sender should implement reasonable delays between retries. Using a different IP address for each retry makes it also impossible for the message to go past greylisting for the recipients who are using it, as greylisting expects retry from the same IP address as the original attempt to send the message (also, greylisting expects a reasonable delay before retry as well). (Please, don't debate now about greylisting itself and whether it should be used or not. At least it has it's use against botnet spam). A few years ago I ran into this issue and it was an important transactional message, so I try to report it to Sendgrid via some form on their website (sorry, I don't remember details, quite a long time has passed), but it seemed evident that the person responding to me didn't know what I'm talking about and what greylisting is at all - he or she was referring me to documents on their website that had nothing to do with the issue - so I gave up. -- Regards, Jaroslaw Rafa r...@rafa.eu.org -- "In a million years, when kids go to school, they're gonna know: once there was a Hushpuppy, and she lived with her daddy in the Bathtub." _______________________________________________ mailop mailing list mailop@mailop.org https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
