Google error - receiving rate

I am using DO as well and it is a clean miab box as well. I remember back in the days where graylisting was popular I saw similar problems with misconfigurede serveres. Graylisting told them to wait a bit andd resend, they then sent another mail again eight away… And continued to do so over and over again. I cannot see how that could happen with miab though… Just noted that it looked similar back then.