Troubleshooting Email Delivery Issues

If emails sent from your event are not reaching recipients, there can be several possible reasons. Email delivery depends on multiple external factors including recipient email providers, corporate security systems, sender reputation, domain authentication, and email template configuration.

Based on common issues encountered across events, this guide outlines the most frequent reasons emails may not be delivered and what you can do to troubleshoot them.

📧 Eventspot supports two email sending options:

• Eventspot SMTP — default sender such as noreply@event.spot
• Custom SMTP — using your own domain

Using your own SMTP allows emails to be sent directly from your domain and provides greater control over authentication, sender reputation, and whitelisting.

1. Incorrect or Invalid Recipient Email Address

One of the most common reasons for email delivery failure is an incorrect or inactive email address.

What happens

The receiving mail server rejects the message immediately.

Common bounce messages

• User does not exist
• Invalid recipient
• Domain not found

✅ What to do

• Verify the recipient email address
• Check for spelling errors
• Confirm that the mailbox is still active

2. Recipient Mailbox Is Full

If the recipient's mailbox storage is full, their email server may temporarily reject incoming messages.

What happens

Emails may bounce with messages such as:

• Mailbox quota exceeded
• Inbox full

✅ What to do

The recipient will need to clear space in their mailbox before receiving new emails.

3. Email Delivered but Landing in Spam

Sometimes the email is successfully delivered but placed in the spam or junk folder.

Common reasons

• Sender domain not authenticated
• Email provider filtering automated messages
• Low sender reputation
• Spam-like content in the email

✅ What to do

• Ask the recipient to check their spam or junk folder
• Ask them to mark the email as Not Spam
• Add the sender email to their safe sender list

4. Corporate Firewall or Email Security Blocking

Many corporate, government, and enterprise email systems use advanced security filters. These systems can block emails before they reach the user's mailbox.

What happens

• Email never appears in the inbox
• There may be no bounce message
• Personal email addresses receive the message but corporate domains do not

Common reasons

• Corporate firewall blocking the sending server
• Email security gateway filtering automated emails
• Internal IT policies restricting external senders

✅ What to do

The recipient's IT team may need to whitelist:

• The sending email address
• The sending domain
• The sending server IP

⚠️ If using Eventspot SMTP, they may need to allow emails from: noreply@event.spot

For organizations with strict IT policies, sending emails using your own domain through custom SMTP can make whitelisting easier.

5. Images in Email Templates Not Displaying

Another issue sometimes reported is that images included in email templates do not appear in certain email providers (especially Gmail).

Common causes

• Images are inserted using local file paths
• Images are embedded directly in the editor instead of being hosted online
• Image URLs are not publicly accessible
• Image links use non-secure HTTP instead of HTTPS

🖼️ Email providers such as Gmail only display images that are hosted on publicly accessible secure URLs.

✅ What to do

When adding images to email templates:

• Host the image on a publicly accessible server or CDN
• Use a full HTTPS image URL
• Ensure the image link does not require login or authentication
• Avoid inserting images directly from local files

Example of a correct image reference:

https://yourdomain.com/images/event-screenshot.png

6. Sender Domain Authentication Issues

When sending emails using your own domain, authentication is critical for successful delivery.

🔐 Most email providers require these DNS records:

• SPF (Sender Policy Framework)
• DKIM (DomainKeys Identified Mail)
• DMARC (Domain-based Message Authentication)

What happens if these are missing

• Emails may be rejected
• Emails may land in spam
• Email providers may flag the sender as suspicious

✅ What to do

If you are using custom SMTP, ensure these records are properly configured with your email provider.

7. Sender Reputation Issues

Email providers monitor the reputation of sending domains and IP addresses. Poor reputation can affect whether emails are accepted or filtered.

Factors that affect sender reputation

• High bounce rates
• Spam complaints
• Sending to outdated email lists
• Purchased or scraped email databases

✅ What to do

• Send emails only to verified attendees
• Regularly clean invalid email addresses
• Avoid purchased mailing lists
• Maintain consistent sending patterns

💡 Using your own SMTP allows you to build and maintain your domain's reputation independently.

8. Email Provider Filtering or Rate Limits

Email providers such as Gmail, Outlook, and Yahoo sometimes limit how many emails they accept from a sender within a short time period.

What happens

• Temporary delivery delays
• Some emails delivered while others are deferred

✅ What to do

• Avoid sending very large campaigns at once
• Send emails in smaller batches when possible
• Gradually increase sending volume if starting from a new sender

9. Large Attachments

Most email providers limit message size.

What happens

Emails with large attachments may be rejected.

✅ What to do

• Avoid attaching large files
• Use download links instead

Eventspot SMTP vs Custom SMTP

Eventspot provides two options for sending emails:

Eventspot SMTP

• Quick setup
• No DNS configuration required
• Suitable for general event communication

However, since it uses shared sending infrastructure, some corporate networks may apply stricter filtering.

Custom SMTP (Using Your Own Domain)

• Send emails from your own domain
• Configure domain authentication
• Build your own sender reputation
• Simplify corporate whitelisting

🏢 Custom SMTP is often preferred for events with enterprise, corporate, or government attendees.

When to Contact Support

If emails are still not being delivered, please share the following with our support team:

• Recipient email address
• Approximate send time
• Any bounce or error message received
• Whether the email was sent using Eventspot SMTP or Custom SMTP

This information will help our team review delivery logs and assist further.