read the first alert. “ISP throttling detected — Gmail queue backing up.”

You cannot see complaints in your outbound logs. ISPs send Complaint Feedback Loops to a separate inbox or endpoint.

: Total emails received by the server versus emails successfully relayed .

To get a full picture of your mail server's health, focus on these three categories: A. Deliverability Metrics

While CLI tools are powerful, they lack historical graphs and correlation. To truly monitor PowerMTA at scale, integrate it with an observability stack.

PowerMTA includes a built-in web interface (usually on port 8080). It offers a real-time snapshot of: Active queues and connections. Hourly delivery rates. Resource usage (CPU/RAM). Recent bounce categories. 2. Command Line Interface (PMTACONTROL)