Following the ArcGIS Online June 2025 release accessing the Fields under Data tab fails with "An error has occurred. Please try again layer." if a field description has an invalid format (e.g. "null").

Workaround

After this defect is resolved, the Fields page can be accessed even if layer definition contains invalid field descriptions (e.g. "sampledescription"), however, the detailed view of the fields will not show the invalid descriptions present in the layer definition and instead shows 'A brief description of the item is not available'.

Until the resolution of this defect, follow the steps below to correct the invalid field descriptions.

Note: This workflow will clear the description and field value for the problematic fields and these values must be added through the Fields page under Data tab in ArcGIS Online or by updating layer definition using the proper format.

Important note: Before performing this workflow, export the data as file geodatabase (FGDB) as a backup.

1.Navigate to the REST endpoint for the feature service.

2. Click Admin on the top right to access the admin endpoint.

3.Select the layer (containing invalid field description).

4.Select 'Update definition'.

5.Copy the existing layer definition and keep it as backup.

6.Under Fields , search for fields with descriptions of any format different than "description":"{\"value\":\"\",\"fieldValueType\":\"\"}"

For example:

{

"fields":

   [{

     "name" : "Parcel", 

     "type" : "esriFieldTypeString", 

     "alias" : "Parcel", 

     "sqlType" : "sqlTypeOther", 

     "length" : 255, 

     "nullable" : true, 

     "editable" : true, 

     "visible" : true, 

     "domain" : null, 

     "defaultValue" : null,

"description" : "null"

   }]

}

7. Delete the remaining definition from the input box, keeping only the fields for which the descriptions need to be updated. At this stage, the input should resemble the example below (Note: The actual input may vary when executed).

{

"fields":

   [{

     "name" : "Parcel", 

     "type" : "esriFieldTypeString", 

     "alias" : "Parcel", 

     "sqlType" : "sqlTypeOther", 

     "length" : 255, 

     "nullable" : true, 

     "editable" : true, 

     "visible" : true, 

     "domain" : null, 

     "defaultValue" : null,

"description":"{\"value\":\"\",\"fieldValueType\":\"\"}"

   },

{

     "name" : "Site", 

     "type" : "esriFieldTypeString", 

     "alias" : "Site", 

     "sqlType" : "sqlTypeOther", 

     "length" : 255, 

     "nullable" : true, 

     "editable" : true, 

     "visible" : true, 

     "domain" : null, 

     "defaultValue" : null,

"description":"{\"value\":\"\",\"fieldValueType\":\"\"}"

   }

]

}

8.Click Update layer definition.

The Fields page can now be accessed.

Steps to Reproduce