Accessing data failed

Error Message

In some instances, when attempting to open the attribute table or edit the attributes of a hosted feature layer in ArcGIS Online, the following error message is returned:

Error:   
Accessing data failed

Cause

The error may be due to one of the following possible causes:

• The feature layer has a 'string' type field containing attribute values as <Null>. When less than (<) or greater than (>) signs are in a text field in ArcGIS Online, they are interpreted as HTML tags. <Null></Null> are not valid HTML tags and ArcGIS Online is unable to access the data.
• One of the field names contains a special character, such as spaces, hyphens, brackets, or characters such as $, %, and #. For more information, refer to FAQ: What characters should not be used in ArcGIS for field names and table names?.
• The 'Editors can't see any features, even those they add' option is enabled in the editor settings.

Solution or Workaround

To resolve the issue, use one of the following options depending on the cause:

Change the <Null> attribute values to a blank space or supported characters

In ArcMap, create a local copy of the hosted feature layer, and edit the local copy to change the <Null> attribute values to blank spaces, or replace them with supported characters. Refer to ArcMap: Editing a value in a table cell, for the steps to edit values in an attribute table. The image below is an example of the field with the <Null> attribute values changed to blank spaces or allowed characters.

When the edits are made, synchronize the edits with the server. To do this, refer to ArcMap: Synchronizing local edits with the server.

Create a new field without special characters in the field name

In ArcMap, create a local copy of the hosted feature layer, and create a new field in the local copy. Do not include special characters when setting up the field name. Edit the new field to copy the attributes from the field that contains special characters (the old field) using the Field Calculator.

Once the new field is populated with the attributes, delete the old field. To do this, right-click the old field and click Delete Field.

When the edits are made, synchronize the edits with the server. To do this, refer to ArcMap: Synchronizing local edits with the server.

Change the editor settings

In ArcGIS Online, navigate to the item details page of the hosted feature layer, and click the Settings tab. In the Feature Layer (hosted) section, under What features can editors see?, select the Editors can see all features option. Refer to ArcGIS Online: Manage editor settings for more information.