Yup, me too. Apparently I'd had too many ssh failures.
However I have a script that runs twice a day and I was noticing before the blacklisting that it would fail sporadically and report a security error for no apparent reason. I reckon those were confused by DH as hack attempts.
Anyway I've been delisted, they told me I may be relisted in the future - I assume its an automatic process. Hopefully I can figure out what the sporadic failures were being caused by.