ArcGIS Online will only display a couple thousand features at one time. And there are probably many many thousand wells in Texas.
Do this instead. From ArcGIS Online where you go to add the data. Choose instead to search ArcGIS Online
In the search type in
TCEQ_Public_Water_System_Wells
and add them to your map. However, you may still get the error. You need to then go to setting and change the visibility scale so they are not all visible when the whole state is on screen.
If that is the wrong well layer you can just search for Texas Wells. But there are 228 layers that match that.