How to whitelist our emails

Prevent your notifications from being blocked or marked as spam

Updated over a week ago

With unsolicited and unwanted emails becoming a larger problem, email services have made their spam filters more stringent. Unfortunately, these tougher guidelines for filtering can cause legitimate emails to be mistaken as spam. To make sure you continue receiving our messages, we suggest that you add us to your whitelist. A whitelist is a list of email addresses and/or domains from which you want to receive email. Adding an address or domain to your whitelist ensures that emails from that address will not be filtered as spam. You'll need to check with your mail provider or contact your IT administrator (schools and companies) for instructions on how to whitelist a domain within their respective mail systems.


You should add ALL of the following domain names to your email whitelist:

  • horizonwebref.com

  • horizonstaffscheduler.com

  • amazonses.com

You should also add ALL of the following email addresses to your email whitelist:

You may also (optionally) whitelist our sending IP addresses. However, these IP addresses change frequently without notice:

  • 199.255.192.0/22

  • 199.127.232.0/22

  • 54.240.0.0/18

  • 54.85.87.96/32

  • 52.7.88.123/32



Hotmail.com or Outlook.com Email Accounts

See this support article for specific details on whitelisting for @hotmail.com or @outlook.com email accounts.

Network Solutions Email Accounts

See this support article for specific details on whitelisting for Network Solutions email accounts.

Verizon.net Email Accounts

See this support article for specific details on whitelisting for @verizon.net email accounts.

Telus Email Accounts

See this support article for specific details on whitelisting for Telus email accounts.

Shaw Email Accounts

See this support article for specific details on whitelisting for Shaw email accounts.

Yahoo Email Accounts

See this support article for specific details on whitelisting for Yahoo email accounts.

Bell Email Accounts

See this support article for specific details on whitelisting for Bell email accounts.

AOL Email Accounts

See this support article for specific details on whitelisting for Bell email accounts.

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