I have created a map for use in Collector (Android), and have shared it appropriately. I am able to open/view/edit the map on the Collector app on my tablet (Lenovo TAB 2 A10-70F, Android v4.4.4), but when I open the same map on my phone (Moto g6 Play, Android v8), I can't see my layer. In my map list, the thumbnail preview shows the layer, but when I tap on the map, it loads, navigates to the extent, but my layer doesn't show. When I go to the layers screen, it lists the layer, the check box is unchecked, and I can't check it. The layer is hosted on an internal server, and the REST URL is the "lowest"--that is, it ends in \0 (as another forum suggested). I've deleted and uploaded the layer again but to no avail.