This article describes some best practices for avoiding errors when synchronizing local edits to the server from ArcMap to ArcGIS Online. An example of such an error is:
"Error: The local edits were not synchronized to the server. The server took too long to answer."
Synchronize more frequently to prevent timeouts
Frequent synchronization of edits ensure that the latest changes from the service are applied to the local copy in a manageable amount, depending on the size of the data. This prevents request timeouts where each service is automatically released from a client once the maximum time for clients to use a service is exceeded.
Clients can use a service for a certain duration of time once the clients receive a reference to the service. After a specific amount of time, the service is released from the clients.
Synchronizing huge edits may cause a client to use a service exceeding the maximum usage time, resulting in timeouts. As a result, the client loses the reference to the service. For more information, refer to the following document, ArcGIS Help: Timeouts
Overwrite the existing service with an edited local copy
Publish an edited local copy to ArcGIS Online to overwrite the existing service. However, this option replaces all the service properties, data references, tables, and layers in the original service as part of the overwriting process. Hence, it is vital to ensure the GIS resource used for overwriting the existing service is configured based on the clients' specifications. For more information, refer the following document: ArcGIS Help: Overwriting a service in ArcMap
Republish local edits as a new feature service
A new item is created in the ArcGIS Online root folder when local edits are republished as a new feature service. The new item is assigned a new ID although the same name is maintained. Although a new ID is assigned to new items, sharing and other properties such as previously saved symbology or pop-up windows must be reconfigured. For more information, refer to the following document: ArcGIS Help: Publish hosted feature layers