Why REST API File Submission with downloadfrom Header Fails When Using RAMDISK for Temp Directory?

Issue:

When configuring a RAMDISK as the temporary directory using IMDisk, file submissions through the browser interface function correctly; however, submissions via the REST API fail due to issues with the downloadfrom header.

Error Details:

The following error is logged:

[WARNING] 2025.11.03 20:50:22.994: (common.workflow) Workflow block ended with exception, block='ErrorRestResponse', workflow_id='', error='Cannot send message to Frontend' [msgid: 97]

You may encounter the message 'Cannot send message to Frontend' in core.log, while the REST API request returns an error: “err”: “File download rejected due to insufficient disk space”.

Resolution:

Until a fix is available, consider using a physical disk path for the temporary directory instead of a RAMDISK when submitting files via the REST API with the downloadfrom header.