When you try to send emails from your software using Outlook, you can see the error:

'Unable to send all emails. Error with the address. Unknown Error. Check Windows event Log for more details.'

When you check your Windows Event Log, you'll see:

'An error occurred while attempting to establish an SSL or TLS connection. The server's SSL certificate could not be validated for the following reasons:

• The server certificate has the following errors:
• The revocation function was unable to check revocation for the certificate.'

Antivirus and Firewall

To resolve this, check your antivirus or firewall software for any email protection and disable it and attempt to send email again.

If the email sends without error, speak with your local IT support to exclude Sage applications from the email protection element of your security software.

If the issue persists

If the issue persists, follow the steps in our unable to apply webmail settings using email defaults article.