Troubleshooting email-sending issues – Xentral help center

Xentral keeps a record of all your outgoing emails. If an email failed to reach its recipient, the record shows an error message for the email. This can help you troubleshoot your email-sending issues.

Proceed as follows to start troubleshooting:

Go to
- Administration > System > Outgoing mail log or
- Administration > System > Email archive > Outbox tab
You see a table with an overview of all your outgoing emails. You are able to review the contents of the emails in the quick preview (click ) and see the recipient in the To column. CC recipients are underlined, BCC recipients are underlined with a dotted line. You can also find information about the subject in the respective column and about the sender in the column from.
Look at the Error column on the right side. If the email failed to send, an error message is displayed here.
Check the table below to find out about potential causes for the error message and recommended solution steps.

Error message	Potential causes and recommended solution steps
You must provide at least one recipient's email address	No recipients were added. Enter a recipient and resend the email.
Mailer is not supported	The email provider is not supported. Try again with a different provider.
Could not instantiate mail function	Several issues could cause this error: Attachment larger than the email service provider supports it The authentication method, sender email address, or other SMTP settings could be incorrect. Compare the SMTP settings of the email account in Xentral with the settings described by the email service provider.
SMTP error: Could not authenticate	Incorrect authentication method for SMTP or incorrect SMTP username or password.
The following From address failed	The email service doesn't recognize the email address from which the email should be sent. Check if the email address is hosted by the mailing service provider.
SMTP Error: the following recipients failed	The recipient's email address is unknown or doesn't exist. In rare cases, this error could also be related to restrictions of the mailing service provider.
SMTP error: Data not accepted	The mailing service provider doesn't accept emails from that address or user. Possible reasons might be: The mailing service provider doesn't allow the sender email address to be different from the user name. The SMTP user is not allowed to send emails from this address. The address is not a verified sender in the mailing service. The mailing service storage of the recipient is full. The email sending limit of the service provider is exceeded.
SMTP error: Could not connect to SMTP host	The SMTP host name may be spelled wrong or doesn't exist. The other reason could be an incorrect SSL method.
Could not access file	A file that should be sent as an attachment doesn't exist on the server.
Filer Error: Could not open file	A file that should be sent as an attachment can't be accessed. In this case, the file either doesn't exist or you don't have the necessary permissions to access the file.
Unknown encoding	The email-sending encoding is not supported.
Signing error	There might be a problem with the open SSL encryption on the server.

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