The Diagnostics tab exists so that a support conversation can start with facts instead of guesses.
The support report:
Copy Report for Support puts the whole report on your clipboard, and Download .txt saves it as a file. The report contains versions, connections, bridges, recent errors and the technical debug log. It contains no passwords and no API keys.
The debug log:
Underneath the buttons is a table of captured log entries with a timestamp, a level of info, warning or error, the component that produced it, and a plain description with any context values. When a sync fails, the technical detail lands here automatically. There is a toggle to turn debug logging on or off, and a button to clear the debug log. A clean install with nothing wrong shows a green confirmation instead of a table.
System panel:
Plugin version, WordPress version, PHP version, site URL, license status and a masked license key.
Cron status panel:
When the next automatic poll is due, the five minute interval, and how many bridges have been polled. If the next run says not scheduled, the poller is not running and that alone explains a polled source that never fires.
Connections panels:
One row per built in autoresponder showing connected or not connected, with a beta badge where relevant, and a second table doing the same for every pack connector that is registered. This is the fastest way to spot a connection that silently lost its credentials.
Environment panel:
Server software, SSL library, PHP memory limit, max execution time and the total number of activity log entries.
When to use it:
Before opening a ticket, and any time a bridge behaves differently on one site than another.