Issue: 

Emails sent from Salesforce to students are going directly into recipients' spam folders. The emails display the message: "The sender hasn't authenticated this message, so Gmail can't verify that it actually came from them. Avoid clicking links, downloading attachments, or replying with personal information." 

Possible Reason: 

This issue is related to the Email Relay and Deliverability settings in Salesforce. Specifically, it indicates that the emails sent from Salesforce are not properly authenticated, which can lead to them being flagged as spam by email services like Gmail. Authentication issues often stem from missing or incorrectly configured SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), or DMARC (Domain-based Message Authentication, Reporting & Conformance) records in your DNS settings. These authentication mechanisms help email services verify that the emails are legitimately sent from your domain, reducing the likelihood of them being marked as spam.

Solution: 

To resolve this, you should ensure that your Salesforce email relay settings are correctly configured and that your SPF, DKIM, and DMARC records are properly set up to authenticate your emails. Additionally, reviewing and adjusting your email deliverability settings in Salesforce may help improve email deliverability. 

For more information, please refer to:

https://help.salesforce.com/s/articleView?id=000382778&type=1