Administrators frequently report a generic error indicating: "SendEmail returned error: Failure sending email. Please contact your administrator."

What is the best way to troubleshoot this error? What logging functions would display more details?

The cause of this is generally some kind of connection refusal from the SMTP server, but the SMTP server administrator will need to determine more specific information. The SMTP server should have logs that will assist with investigating the specific cause of the error. If the logs do not show a connection attempt from the Transfer Server IP address, then that also provides information showing that the connection may be blocked at the firewall level from the Transfer server, or another device is blocking the connection on the way. 

See this documentation about the Email tab of the Config Utility for more information: 
MOVEit Transfer Config Utility - https://docs.progress.com/bundle/moveit-transfer-web-admin-help-2025/page/MOVEit-Transfer-Config-Utility.html

Running the MOVEit Transfer Check utility on the server can give more information as to the cause as well. Enter an admin user's credentials, then review the status of the Send Email test.

The SMTP Admin will identify more information about this error, but likely resolutions steps include:  

• Open the firewall port 25 or other intended SMTP port. For more information, see this documentation: Firewall Configuration - https://docs.progress.com/bundle/moveit-transfer-web-admin-help-2025/page/Firewall-Configuration.html
• Examine the SMTP server to determine if it is expecting Username/Password credentials. 
• Identify if the server requires a SSL certificate validation to connect. 
• Check the network route to the SMTP server.
• SMTP Admins must allow the mailbox to have SMTP Auth enabled on the server. 

Progress Article(s):

If an error about the SFTP server not accepting credentials presents in the logs, see this article: MOVEit Transfer Cannot Connect to an SMTP Server with a Username and Password