My company rents an email host, but I just noticed sometimes an email takes around 5 hours to deliver and it's unacceptable.
I went to complain to the host, and they said they needed proof; as it just happens in random situations, it's hard to "catch" the moment.
Is there a way to test the mail delivery? Such as a program that can send an email every 15 min? Or any suggestion to get proof?