Which Feature Service REST URL to use for GeoEvent Server

[TimHayes3]

I want to add my GeoEvent Feature Service to Map Viewer Classic in AGOL. I need to know which URL is the right one to use:

https://mygis.mycity.gov/mymachine/rest/services/GeoEventMap/FeatureServer 

or 

https://mygis.mycity.gov/mymachine/rest/services/GeoEventMap/FeatureServer/0  

I already added the 2nd one as a layer to Map Viewer Classic and it seems to be reading the events. But want to make sure this is the correct one to add. 

Thank you.