After experiencing some ArcGIS Online service issues, we have implemented a few service configuration changes and behaviour changes to improve the stability.
The change that may affect users is the visibility range of Nearmap imagery, which is set at 1:5,000,000. The initial zoom of the map depends on the application. If it happens to be smaller scale than 1:5,000,000, the users may not see anything, and will have to zoom in to be able to see the Nearmap imagery.
If you are having trouble viewing our imagery since this change, we recommend that you add a basemap to assist you in referencing where Nearmap's imagery is: