That build error indicates that the transit stop has not successfully connected to a street feature. There are a couple of likely reasons for this:
- The street dataset you're using does not cover the entire geographic area that your transit system covers, so there are some stops that cannot find a street to snap to.
- There are some transit stops in your GTFS data that are in the wrong geographic place. For example, you might have a few stray stops in the middle of the ocean or in Antarctica or something because the lat/lon coordinates are wrong.
- Your street data covers the correct geographic extent, but it is missing some smaller roads or sections where there are transit stops, so the stops cannot find anything to snap to within the search tolerance.
- The search distance you used when running the Connect Network Dataset Transit Sources To Streets tool was too small, and for some reason, your transit stops are offset significantly from the street centerlines. For this reason, they failed to snap to the streets.
I think you need to take a close look at both the locations of your transit stops and also your street data to determine which of the above cases is causing your problem. Once you've determined that, then you can figure out how to fix it.
If the problem is only for a few stops, and they're in an area where you don't expect them to be used for your analysis, then you can safely ignore the build errors. The rest of the network will continue to function. Otherwise, you will need to resolve the issue. You might need to edit the stop locations (or correct the original GTFS and start over), update your street data or use a different street dataset, or re-run Connect Network Dataset Transit Sources To Streets with a larger search tolerance.
