You are sharing an m-aware layer as a web feature layer or as a web scene layer with an associated web feature layer. If you are editing the web feature layer through REST or SOAP endpoints, you will be unable to edit feature geometry unless you supply an m-value with the edit.
Solutions
Do one of the following:
- Do nothing. This is okay if you will not be editing feature geometry or if you will be editing but supplying m-values with the edits.
- Alternatively, you can remove the layer from your map if it is not needed.
More information
If you have data that has m-values, these features can be deleted, new features can be inserted, and the attributes of existing features can be edited but the geometry cannot be edited. All new features will have their m-values set to NaN when inserted through the REST and SOAP endpoints. If features with m-values are edited through the web feature layer in ArcGIS AllSource with the local editing commands, all editing operations are supported.
For more information, see Analyze your GIS resource.