Outgoing Email Being Blocked

Hi,

I have an email ID wherein the outgoing mail are being blocked the user get an email which is as follows:

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Dear User,

Mail Outgoing blocked. Reason :Mail rate exceeded limit

However, we realize that this might have been unintentional. To unblock, please click here.

Thanks,

Zoho Mail Team

P.S.: This is an auto-generated message. Please do not reply to this email.

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Please let us know what is the 'mail rate exceeded limit', and if there is a way to unblock the same immediately if the issue occurs. Also let us know if there is any purchase to be made for increase the limit. Since this is a critical Id we cannot afford mails being blocked.

Thanks,

Sharieff