You have received a phishing email that appears to come from the school loop servers (for example firstname.lastname@example.org) and you would like to know how to block these emails.
These emails were likely not sent from email@example.com or the SchoolLoop mail servers. This appears to be a spoofing attempt where spammers falsely assume the identity of known senders (School Loop in this case) to send spam.
You can stop spoofing spam by enabling SPF (Sender Policy Framework) on your spam filters, refer to the article Domain and Address Range Needed for the schoolloop.com SPF Record for more information.
When SPF check is enabled on your anti-spam solution, it will check the IP address for all incoming school loop emails to validate if they are indeed coming from authorized servers. Therefore, it will block any spoofed email.
If you believe the email came from a genuine SchoolLoop IP address, please open a support ticket and download the email file (.eml) and share it as an attachment for investigation.