Hi! I'm not lucky. One of mi ispconfig email server has benn blocked bay Yahoo and I'm desperate because although I've opened various cases with Yahoo support team, they clean their hands about the problem. When I send an email to Yahoo/AOL destination I recieve this: host mta7.am0.yahoodns.net[184.108.40.206] said: 421 4.7.0 [TSS04] Messages from xxx.xxx.xxx.xxx temporarily deferred due to unexpected volume or user complaints - 220.127.116.11; I've checked all Ispconfig configuration (like mail traffic, dns reverse, ptr, dkim...), I'm not blacklisted by common spam lists (I've used mxtoolbox) and all seems to be ok. Even I've waited for two days without send email to Yahoo. Nothing works. Then, searching over internet I've found this post: rackaid.com/blog/yahoo-defers-cpanel-mail/ This says there's a parameter that could be modified and solves the problem but I can't find that on Ispconfig. The parameter is hosts_max_try_hardlimit and the solution passes for reducing the number of retries of email delivery to each server. ¿There's something like this in Ispconfig??? Thanks.