I hate to say this but this is just wrong. I am with Telekom in Germany and they have actually very reliable exchange servers. I use many forums which send emails to me for verification. These mails I receive within seconds, not minutes. This OTP is fine by me, IF you would get your servers set up properly to send mail. The delay isn't from my Provider, the delay is in getting to my provider. This delay isn't from "delays between hops", that's just a sad excuse for not knowing what you're doing. If this were the case, I would be having this same issue with random other instances, which I don't. So far I've been through 4 OTPs while writing this, each with a 5 minute delay or more. It's NOT my provider and it's NOT the hops, if you implement something, test it first.