Step by step

Open NWK again from its icon, as usual.
Check the dots next to LIVE: green means a destination is on air.

If the window closed

The stream, the recording and the external outputs keep running even without the window. Open NWK again from its icon: it takes back control of what's on air, without interrupting anything.

Closing only the window on purpose

If you close NWK while on air or recording, it asks what to do:

Close interface only: keeps the stream, recording and external outputs running.
Stop everything: ends the stream and finalizes the recordings.

If everything stopped

If all of NWK closed unexpectedly, when you open it again the session comes back as it was, and the program tells you the previous session was restored. With the recovery option on (it comes on by default), the stream and the recording that were active come back by themselves. See NWK reopens the way you left it.

The recording up to that point is saved

The recording is made in 1-second blocks. If the computer shuts down or the program closes midway, the file up to that point is still playable.

To help support understand what happened

After the event, send a report to support.

The program closed during the stream