I have to suspend the account registration via Outlook and Hotmail emails because with same accounts, the hotmail/outlook (Microsoft provider) could have as many aliases as possible. I have observed many spam registrations (with obvious same account email aliases).
There is no good solutions to this, as the emails look totally different. Gmail addresses can be detected as the dots and labels (+) can be easily identified.
However, if you do want to use hotmail or outlook to register, please contact me at justyy [at] zoho.com and I'll take a look and approve it case by case.
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