Attempting to update attachment keywords without including a file when using the ArcGIS REST API in ArcGIS Enterprise returns the error message, "Unable to find uploaded item information. null".

Workaround

In order for the operation to be successful, a file must be included in the POST request for the Update Attachment operation. Another alternative is to host the feature layer in ArcGIS Online if there is a need to update attachment keywords without re-uploading the file.

Steps to Reproduce