Most problems sending emails happen because the email server settings, credentials, or permissions have changed outside Donorfy.
This article walks you through the first checks to make, then explains the most common error messages and how to resolve them.
⚠️Important:
Many fixes require changes on your email server. You may need help from your IT team, email host, or Microsoft/Google administrator.
Traditional on-premises email systems (such as Microsoft Exchange) are often locked down, which can make it hard for external systems to send via them.
As an alternative, you can use a cloud account (for example, Office 365) for Donorfy emails, and configure that service to forward or route mail to your internal server if needed.
Troubleshoot Email Sending Errors
Check Your Email Server Password First
Before investigating specific error codes, always confirm that the email server settings in Donorfy are still valid.
Go to Settings, click Configuration.
Select Email Server Settings.
Make a note of all existing settings (server type, email address, username, etc.).
Click Clear settings.
Re-enter the same settings you noted, but:
Make sure you enter the current password for the mailbox.
Save the settings, then complete the authorisation flow if required (for example, Office 365 authorisation).
Try sending an email again.
If emails still fail, use the error message returned to identify the section below that applies.
Fix Authentication and Connection Errors
Error: SMTP server requires a secure connection / Client not authenticated (535 / 5.7.57 / 5.7.139)
Example message:
The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.57 Client not authenticated to send mail. Error: 535 5.7.139 Authentication unsuccessful, the user credentials were incorrect.
This means the username or password for your email server is no longer valid.
Update your email credentials in Email Server Settings as described in section 1.
Confirm you are using the correct email address / username for the mailbox.
Save and re-authorise if prompted.
Test sending again.
If the error continues, your email administrator may need to confirm that the account is not locked or restricted.
Error: Exception in SendEmailAsync Code: generalException Message: An error ocurred sending request
This usually indicates the connection to your email provider has been lost, often because:
The password changed.
An authorisation token was revoked or expired.
Follow the steps in Check Your Email Server Password First.
If you use a token-based connection (for example, Office 365 OAuth), repeat the authorisation process in Email Server Settings.
Test sending again.
If the problem persists, your email administrator may need to check for blocked connections or app restrictions.
Office 365: (401) Unauthorized
This error can be caused by:
Incorrect email address or password.
Problems with how Office 365 is allowing apps like Donorfy to connect.
Changes to authentication (for example, Multi-Factor Authentication).
Try the following:
Double-check the email address and password in Email Server Settings.
If the details are correct, run Microsoft’s troubleshooting tool:
Download and run the Support and Recovery Assistant for Office 365 on a computer with Outlook installed.
Choose Outlook as the app you have problems with.
Select I need help setting up Office 365 email in Outlook.
Follow the prompts and review any issues the tool reports, then apply the suggested fixes.
If your Office 365 account has Multi-Factor Authentication (MFA) enabled:
Update your Donorfy Email Server Settings to use the newer Office365 connection type rather than basic SMTP.
Follow the Sending Emails from Donorfy guidance to complete the Office 365 authorisation.
Error: 5.7.57 SMTP; Client was not authenticated to send anonymous mail during mail from
Often this means the email address you entered is not the actual Office 365 mailbox address.
Sign in to office.com with the mailbox account.
Click your profile (top right) to see the actual mailbox email address, which may look like:
account@company.onmicrosoft.comMake sure this exact address is used as the From / account email in your Donorfy Email Server Settings.
Save and re-authorise, then test again.
Also confirm the password in Donorfy matches the current mailbox password.
Fix Office 365 / Exchange “Send As” Errors
Errors: SendAsDeniedException or Mailbox unavailable. 5.3.4 / 5.2.0 STOREDRV...
Examples:
5.2.0 STOREDRV.Submission.Exception:SendAsDeniedException.MapiExceptionSendAsDenied; Failed to process message due to a permanent exception...
Mailbox unavailable. The server response was: 5.3.4 554-554 5.2.0 STOREDRV.Deliver; delivery result banner
These errors often occur when Donorfy is connected using the Manual Setup option for Office 365 or Exchange.
To fix this:
Go to Settings, click Configuration, select Email Server Settings.
If your server type is:
Office 365 Manual Setup, change it to Office 365; or
Exchange Manual Setup, change it to Exchange.
Confirm the email address is correct.
Click Save changes.
Click Authorise Office365 (or equivalent) and complete the authorisation process.
Save again, then test sending.
Error: Mailbox unavailable. The server response was: 5.7.1 Client does not have permissions to send as this sender
This means the account Donorfy is using is not allowed to send as the configured “From” address.
You must configure Send As permissions on your mail server so the account Donorfy uses can send mail as the outbound mailbox.
For guidance, see:
Exchange 2007 & 2010: Configure Send As permission in Exchange
Office 365: Grant Send As permissions in Office 365
Google Workspace (Google Apps): Send on behalf in Gmail
If you use a different email server or still have issues, your email administrator or hosting provider must apply the correct Send As permissions.
Error: Mailbox unavailable. The server response was: 5.7.60 SMTP; Client does not have permissions to send as this sender
This is another permissions-related error, common with Office 365, and usually caused by a mismatch between:
The From email address you use in emails, and
The mailbox address configured in your Email Server Settings.
To resolve:
Check the email address configured in Email Server Settings (the From account).
Make sure all emails you send use this same From address.
If you have templates or manual emails that use a different address (for example,
donations@mytestcharity.com) but your mailbox istest@mytestcharity.onmicrosoft.com, update the From address so they match.Save changes, then test sending again.
4. Fix Relay and Access Errors
Error: Mailbox unavailable. The server response was: 5.7.1 Unable to Relay
This usually indicates your email server is rejecting the message because:
Relaying is not allowed from Donorfy’s IP or host.
The sending account does not have permission to relay messages.
To fix this, your email administrator must update the mail server’s relay / security settings to allow Donorfy to send via that server. This may involve:
Allowing authenticated relay for the sending account.
Creating a connector or rule for the Donorfy IP or hostname.
Adjusting anti-spam or firewall policies.
Contact the person or organisation that manages your email server for help.
Fix Autodiscover and “Server Could Not Be Located” Errors
Error: Your email server could not be located - Exception in ExchangeServices. The Autodiscover service couldn't be located.
This indicates the Autodiscover service for Exchange is not available or not configured correctly.
To resolve:
Ask your Exchange administrator to ensure Microsoft Autodiscover Service is enabled and correctly configured on the Exchange server.
After Autodiscover is fixed, re-run the email server configuration in Donorfy:
Go to Settings, click Configuration, select Email Server Settings.
Re-select the appropriate server type (for example, Exchange).
Save and authorise if needed.
Test sending again.