Some ISP's, Web Hosting Companies and free email providers have limits on how many emails you can send a day.
If you try to send more email than the hourly or daily email sending limits of your mail server, you will notice errors being returned after the specified quota is met, saying something along the lines of:
You have reached your daily sending quota.
In PhoneBurner, while trying to turn on your Custom Email Sending Server(formerly SMTP Server), you may see this:
We were unable to activate your SMTP server because there was an error sending a test message. Please update your settings, then try enabling again.
Response from server:
Expected response code 354 but got code "550", with message "550 5.4.5 Daily user sending quota exceeded. c7-v6sm63179055pfg.81 - gsmtp "
If you surpass the daily SMTP email sending limits of your provider, you will generally have to wait 24 hours before you can send more emails through that particular server.
To find out what the hourly or daily email sending limits are for your email server, we recommend checking with your email provider for the most current information.
Here are some links to some common provider limits:
Microsoft Office 365 has very complex limits, including being limited to 30 messages per minute ( at the time of this writing).
If your mail server has limits that don’t support the size of your calling/emailing list, you have a variety of options:
1. Contact the host of your outgoing SMTP mail server(s) and ask if they have a business account that lets you send more emails each day to support your business.
2. Use a 3rd party outgoing SMTP service such as SendGrid, Smartpost or TurboSMTP to relay your large email campaigns.
3. Find a web hosting company who has daily email sending limits that meet your needs.
4. Setup your own MS Exchange Server and configure it for SMTP email delivery.