There had been a steadfast number of requests for blocking and unblocking Zoho Mail because Zoho Mail is aggressive to block accounts if there is perceived amount of spam-like activity. I have the following suggestions:

1. Can you bring in a automatic unblocking based on account history and some little heuristics which can help this? If there are brute force hard core spammers you can then retire their accounts from the catalog itself.
2. Also a small utility near Zoho Mail Discussions section for 'Unblock' would help these requests do not inundate Zoho Discussions would also help.

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Deepak Vasudevan
http://thamizhththendral.blogspot.com/