Zoho Mail as a service is designed to support Business(1-1) communication and we do not recommend sending Bulk mailers using our servers and that includes both within and outside your Zoho Mail Domain. We have restrictions imposed to ensure the reputation of our service, as well as your domain, is not affected.
The limit for the number of emails/recipients allowed in an email when sent through Zoho Mail is high enough to ensure that normal email communication is not treated as spam. They are set as dynamic and are determined by our Spam Engine based on the algorithms we have implemented.
We have spam filtering limits imposed due to which you will not be allowed to send any kind of mass emails/ promotional emails or marketing emails. This restriction is common for all users across Zoho Mail irrespective of the subscription you are in. The reason for having these limits is to protect the reputation of our services and also to avoid our IP getting Blacklisted.
Having said that we also would like to inform you that you should have no trouble sending 300 emails/day using your Zoho Mail account. However, please avoid sending emails altogether at once. Instead please try sending in batches.
Please try sending emails in compliance with our Usage Policy below to avoid getting banned:
https://www.zoho.in/mail/help/usage-policy.html#alink1
>> If you are looking to send bulk Marketing/Promotional emails, please try Zoho Campaigns.
>> If your requirement is to send Transactional emails please try Zoho Transmail.
Zoho TransMail plugin -> https://www.ads-software.com/plugins/transmail/
Regards,
Srinath.
