Hmmm....it seems like that could be caused by several things. Is it an extremely large data set? It could also be an issue with the geometry, in which case you would need to run the "repair geometry" tool in ArcMap and then republish. You could also try rebuilding the spatial indexes through the feature layer settings tab, that's helped me a few times in the past, when point feature layers weren't drawing even though there were only a few points in them.
You might also have better luck calling Esri support so you can do a screenshare session and show them exactly what's going on.
Best of luck!
Best,
Katie
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