PROBLEM
In ArcGIS Online, when viewing a hosted feature layer with custom point symbology published from ArcMap, the custom point symbols do not display or the symbols appear generalized.
Symbology from custom style reference files in ArcMap is not always supported in ArcGIS Online. Based on ArcGIS Online: Troubleshoot, some symbols may be downgraded when published to ArcGIS Online because web browsers cannot display some of the more complex cartographic symbology.
Perform the following steps to resolve the issue.
Get help from ArcGIS experts
Download the Esri Support App