Help & Support

Get help with Email Sandbox issues and find answers to common questions

Find answers to common questions and troubleshoot issues with Email Sandbox. Our comprehensive help resources are designed to get you back on track quickly.

Resources

Frequently Asked Questions

Browse our comprehensive FAQ section for quick answers to common questions about Email Sandbox setup, integration, testing features, and best practices.

Troubleshooting

Step-by-step solutions for common issues including connection problems, email capture issues, and configuration errors.

Common issues & solutions

Connection issues

Can't connect to Sandbox SMTP

1. Verify credentials: Check username and password
2. Confirm port: Use 2525, 25, 587, or 465
3. Check firewall: Ensure ports aren't blocked
4. Test connection: Use telnet or nc command

telnet sandbox.smtp.mailtrap.io 2525

Emails not appearing in Sandbox

1. Check sandbox limits: Free plan has 500 emails/month
2. Verify credentials: Ensure using correct sandbox
3. Check spam folder: Some emails may be filtered
4. Review email size: Maximum 5MB including attachments
5. API rate limits: Check if hitting rate limits

Configuration problems

Framework integration not working

• Laravel: Clear config cache with php artisan config:clear
• Rails: Restart server after config changes
• Django: Check EMAIL_BACKEND setting
• Node.js: Verify environment variables loaded

Authentication failures

535 5.7.0 Invalid login or password

Solution:

• Copy credentials directly from Mailtrap dashboard
• Don't use email address as username
• Regenerate credentials if needed

Testing issues

HTML not rendering correctly

• Use HTML Check tool to validate code
• Test with different email clients
• Check for missing closing tags
• Validate CSS compatibility

Attachments not working

• Verify file size < 5MB total
• Check MIME type configuration
• Ensure proper encoding (base64)
• Test with different file types

Getting help

Self-service resources

1. Search documentation: Use the search bar above
2. Check FAQs: Frequently Asked Questions
3. Review troubleshooting: Common issues
4. API reference: API Documentation

Contact Support

If you can’t find the answer you need in our documentation or something doesn’t work as expected, feel free to contact our support team and speak with an agent, we’re here to help.

If the information provided (including AI responses) doesn’t fully resolve your question or your case requires a closer look, our team can review your setup and assist further.

You can get in touch with the Mailtrap Support team using one of the following ways:

• From your Mailtrap account

1. Log in to your account here.
2. Go to the Help Center > Get Help
3. Click Start conversation.

• Email us at 📧 [e-mail]

Whether you need technical assistance, help troubleshooting UI or account-specific issues, or simply want to talk to customer support, our team will be happy to assist you.

Before contacting support

Please have the following information ready:

• Account email address
• Sandbox ID or name
• Error messages (exact wording)
• Steps to reproduce the issue
• Framework/language you're using
• Code snippets (if applicable)

Quick solutions

Email capture issues

Problem	Solution
No emails received	Check credentials and connection
Emails delayed	Normal processing time is < 1 second
Missing emails	Check inbox limits and filters
Partial content	Verify email size < 5MB

API issues

Error Code	Meaning	Solution
401	Unauthorized	Check API token
403	Forbidden	Verify permissions
404	Not found	Check inbox ID
429	Rate limited	Implement backoff
500	Server error	Retry or contact support

SMTP errors

Error	Cause	Fix
Connection refused	Wrong port/host	Use sandbox.smtp.mailtrap.io:2525
Authentication failed	Invalid credentials	Copy from dashboard
Message rejected	Size limit exceeded	Keep under 5MB
Timeout	Network issue	Check firewall/proxy

Debugging tools

Connection testing

# Test SMTP connection
openssl s_client -connect sandbox.smtp.mailtrap.io:2525 -starttls smtp

# Test with curl
curl -v telnet://sandbox.smtp.mailtrap.io:2525

Email testing

# Python test script
import smtplib
from email.mime.text import MIMEText

def test_sandbox():
    msg = MIMEText('Test email body')
    msg['Subject'] = 'Test Subject'
    msg['From'] = '[e-mail]'
    msg['To'] = '[e-mail]'

    with smtplib.SMTP('sandbox.smtp.mailtrap.io', 2525) as server:
        server.login('YOUR_USERNAME', 'YOUR_PASSWORD')
        server.send_message(msg)
        print("Email sent successfully!")

test_sandbox()

Best practices

Optimal configuration

• Use port 2525 for best compatibility
• Enable STARTTLS for security
• Set reasonable timeout values
• Implement retry logic
• Use connection pooling

Testing strategy

• Create separate sandboxes per environment
• Clear sandboxes regularly
• Use descriptive email subjects
• Tag emails with test IDs
• Automate common tests

Team collaboration

• Share sandboxes appropriately
• Document sandbox purposes
• Use consistent naming
• Regular permission audits
• Communicate test schedules

Community resources

Tutorials & guides

• Getting started video
• Blog tutorials
• Integration examples

Developer resources

• API client libraries
• Postman collection
• Code snippets

Feedback & suggestions

We welcome technical feedback and contributions that help us improve Mailtrap’s functionality and documentation. Please use the appropriate channel depending on the type of request.

Bug Reports

If you encounter a product issue or unexpected behavior, please Contact Support.

To help us investigate efficiently, include:

• A detailed description of the issue
• Exact reproduction steps
• Relevant stream, domain, sandbox, or account details
• Timestamps (including timezone)
• Screenshots or logs if available

Feature Requests

For product improvements or new feature proposals, use our Public Roadmap portal.

There you can:

• Submit a new feature request

• Upvote existing requests

• Subscribe to updates for specific requests

🔜The following enhancements are currently planned:

• GraphQL API
• Advanced search filters
• Email templates library
• Browser extension
• Mobile app

Documentation Improvements

If you identify unclear, incomplete, or outdated documentation:

1. Use the feedback widget located on the right-hand side of the page to rate the article:
2. Provide specific feedback describing what should be corrected, clarified, or expanded

This helps us continuously refine our docs.

GitHub & Technical Collaboration

For open-source projects, SDKs, or public repositories, join us on GitHub.