Logs

Interface Server → Logs shows what the engine itself did — as distinct from
Messages, which tracks individual messages. When a message
never appeared at all, this is where the reason usually is.

Filtering

Filter	Notes
Interface	Narrow to one route, or leave as All
Info / Warning / Error	Severity. Start with Error
Start Date / End Date	The window to search
Instance	Filters by engine process. Instances are managed by Intely, so this list is typically empty for a customer organization — filter by interface instead

Each entry shows its Type (severity), the Log Line, and when it was recorded.

What turns up here

The entries that matter are usually about messages that never became messages:

A source that cannot be read — a watched directory that does not exist or is not readable
will log an error on every polling attempt. A route showing zero received messages while the
sender insists it is delivering almost always looks like this.
A file that was refused — a file that cannot be parsed is logged with the reason and,
where useful, the beginning of the message, along with which attempt it was and when the next
retry is due. Retries mean a transient problem may resolve itself; a malformed message will
not.
Encoding problems — a message whose encoding cannot be determined. Frequently a line
ending issue, which the Normalize Line Endings option on the interface's source exists to
handle.

Using it with the other pages

A useful order when something is wrong:

Interfaces — is the route running, and are its counts moving?
Logs — filtered to Error, for the route in question. Did anything arrive and get refused?
Messages — for messages that were accepted, what happened at each destination?

Working in that order separates "nothing arrived", "something arrived and was refused" and
"something arrived and could not be delivered" — three problems with three different causes.