Testing your campaign is an important step to see how merge fields are rendering and how the email looks like in a recipient's inbox. Sometimes test emails may land in the spam folder, not arrive at all or take a longer time to deliver.
Here's are the most common reasons:
Delivery can take up to 15 minutes. While most test emails arrive within a minute it may take up to 15 minutes depending on the email provider you are using. If the test email does not arrive after 15 minutes, please reach out to support
"From" and "To" email address or domain is the same. If these two email addresses are the same, you may not receive the test email as it can get blocked or go to your spam folder. To resolve, make sure that the From and To email addresses are different. You may also experience deliverability issues with the test email if the “From” and “To” email address are on the same domain. To resolve, simply send to a different domain.
Test email gets quarantined by your firewall. Some spam firewalls are very strict with test messages as it looks like a phishing attempt or spam message. Ask your IT professional to release the test email from quarantine and whitelist the IP address.
Test email includes unrendered merge fields or spammy content. Due to this your test email might land in the spam folder. To resolve, mark the email as "not spam".