You are either sharing a web scene that contains a multipoint layer or are sharing a multipoint layer as a web scene layer. Multipoint layers cannot be drawn as part of a web scene.
Solutions
- If you are sharing a web scene, remove the multipoint layer from the scene.
- If you are share a web scene layer, use the Multipart To Singlepart tool to separate the parts.
More information
Neither existing web feature layers that contain multipoints nor new web layers containing multipoints are supported in web scenes.