Understanding Email Delivery Issues

Attachment Size Limit: The maximum attachment size allowed by VanillaSoft is 12MB. Emails with attachments exceeding this size may not be successfully delivered to the recipient, and notably, VanillaSoft does not provide an error notification when this occurs as the block happens outside of our visibility.

Does Size Matter? Email standards like MIME do not set specific file size limits, but practical limitations often arise during email transmission. Emails often pass through several mail transfer agents before reaching the recipient, each potentially imposing its own size limits due to storage constraints. This can make sending large attachments unreliable, especially over the internet.

• Example: When Gmail increased its attachment size limit to 25MB, it noted that users might still encounter issues sending large attachments to recipients using other email services with smaller limits. Generally, a 10MB file size is considered safe for avoiding issues across various email services.

• MIME Encoding Overhead: It's also important to remember that MIME encoding adds about 33% overhead to file sizes. For instance, a 20MB document on your disk might exceed a 25MB email attachment limit after MIME encoding.

Daily Sending Limits: Some providers, like Gmail, impose daily sending limits to prevent spam and secure accounts. If you exceed these limits, your ability to send further emails may be temporarily blocked.

Provider-Specific Limits:

• Gmail for Personal Use: There are specific sending limits which can be found in Gmail's support documentation.
• G Suite Accounts: Enhanced sending limits applicable for business users.
• Outlook.com and Exchange Online (Office 365): Each has its own set of limits regarding how many emails can be sent and received.

Check with Your Provider: If you've configured VanillaSoft with your own mail server (e.g., Gmail), and you're experiencing issues, it's crucial to refer to the respective service's guidelines on sending limits. These limits may change over time, and your organization’s IT administrator might also impose additional restrictions.

• Monitor Attachment Sizes: Keep the size of your attachments well within the limits for broader compatibility.

• Stay Informed About Provider Limits: Regularly check for updates on the sending and receiving limits imposed by your email provider.

• Consult IT and Support Articles: For detailed guidance on sending limits and troubleshooting, refer to provider-specific resources or articles like "Gmail sending limits in G Suite" and "Exchange Online Limits."