Error: "Could not convert socket to TLS" due to SMTP hostname mismatch in VCF Usage Meter 9.x

Products

• VMware Usage Meter

Issue/Introduction

When configuring or saving SMTP email notification settings in the VCF Usage Meter 9.x Web UI, the operation fails with the following error:

General error occurred while sending mail - Could not convert socket to TLS.

Environment

VCF Usage Meter 9.x

Cause

The appliance attempts a STARTTLS upgrade but the UI-configured SMTP hostname does not match the server's certificate CN/SAN

Resolution

1. Identify the Certificate identity: Run the following command from the Usage Meter console to view the certificate presented by the SMTP server:
   openssl s_client -connect <SMTP_SERVER_IP>:25 -starttls smtp
   
   
2. Look for the Subject (CN) or Subject Alternative Name in the output.
   
   
3. Update Usage Meter Configuration:
    Log in to the Usage Meter Web UI.
    Navigate to Settings > Email.
    Update the SMTP Server field to the FQDN that matches the certificate identified in Step 1.
   
   
4. Handle DNS Resolution (If necessary): If the matching FQDN does not resolve to the SMTP server's IP via your DNS provider, add a local entry to the appliance:
   Edit the hosts file: vi /etc/hosts
   Add the mapping: <SMTP_IP_ADDRESS> <MATCHING_FQDN>
   
   
5. Restart services:
   

   /opt/vmware/cloudusagemetering/scripts/stop.sh all
/opt/vmware/cloudusagemetering/scripts/start.sh all

Additional Information

Error: "Saving email notification settings failed: The mail test connection attempt failed." when saving email notification settings