When running a Custom Powershell script using a Custom Orchestration Activity, it is generating the following error below.

Getting SEVERE *** ERROR *** Failed while executing script<random character sequence>.PS1 (Access denied)

This issue could be due to Permission or Credentials related.

1. Check whether the service account running the MID server service has permission to run the script in windows\temp.
2. Test couple of simple PowerShell command like "ls"
3. Check to see if there is a Credential tag on the Custom Activity and make sure that the same tag exists on the credential table.
4. Test the credential with the target IP to make sure that the credentials works.
5. On this particular issue, the error was generating due to a broken credential record.