Why emails fail to send?

When you send an email from OnePageCRM, it goes through your connected email provider (Gmail, Outlook, or SMTP). Sometimes the provider rejects the email or can't deliver it. When that happens, the email gets a Failed label in OnePageCRM.

The reason for the failure comes from your email provider, not from OnePageCRM.

Here are the most common causes and what you can do about each one.

In this article:

These are situations where nothing is wrong with the email itself. The issue is temporary, and resending the email later will likely work.

You hit your provider's sending limit

Email providers cap how many emails you can send per day or per hour. For example, some SMTP providers allow 300 emails per day or 75 per hour. If you exceed that, additional emails fail until the limit resets.

👉 What to do:

1

Wait for the limit to reset (usually one hour or 24 hours, depending on the provider).

2

Resend the failed emails from the Failed send folder.

3

If you regularly hit limits, contact your email provider about increasing your quota or spread your bulk sends across multiple days.

Your email provider had a temporary outage

Server errors and timeouts happen when your provider's servers are temporarily unavailable or overloaded.

👉 What to do:

1

Wait a few minutes and resend the failed emails from the Failed send folder.

2

If the issue persists, check your provider's service status page.

Your provider is throttling requests

This is similar to sending limits, but applies to how fast requests are processed.

If too many emails are sent in a short burst, the provider may temporarily reject some.

👉 What to do:

1

Wait a few minutes and resend the failed emails from the Failed send folder.

2

For large bulk sends, consider sending in smaller batches.

Below are failures that have a root cause that won't go away by simply resending.

You need to fix the underlying issue before trying again.

Authentication error or expired credentials

Your email provider rejected the connection because your login credentials are no longer valid. This can happen when you change your email password, revoke app permissions, or your OAuth token expires.

👉 What to do:

1

Go to Email configuration in OnePageCRM.

2

Disconnect and reconnect your email account.

3

Resend the failed emails from the Failed send folder.

Outlook: "SendAsDenied" error

Your Microsoft 365 admin hasn't granted you permission to send from the email address connected to OnePageCRM.

This is common in organizations where email aliases or shared mailboxes are used.

👉 What to do:

1

Ask your Microsoft 365 administrator to grant "Send As" or "Send on Behalf" permission for your email address.

2

Reconnect your email in OnePageCRM if needed.

3

Resend the failed emails from the Failed send folder.

Outlook: account suspended

Microsoft has suspended your email account, usually due to suspicious activity or a policy violation.

👉 What to do:

1

Sign in to your Microsoft account directly and follow the steps to reactivate it.

2

Once reactivated, reconnect your email in OnePageCRM.

3

Resend the failed emails from the Failed send folder.

Outlook: quota exceeded

Your Outlook mailbox has reached its storage or sending quota.

👉 What to do:

1

Free up space in your Outlook mailbox by deleting old emails or emptying the trash.

2

Check your Microsoft 365 plan's sending limits with your admin.

3

Resend the failed emails from the Failed send folder.

Message too large

The email (including attachments) exceeds your provider's size limit. Gmail allows up to 25 MB, and Outlook allows up to 20 MB.

👉 What to do:

1

Reduce the size of your attachments or use a file-sharing link instead.

2

Resend the failed email from the Failed send folder.