Mass Action Scheduler

Hi Srikanth, 

This is usually because the Mass Action Scheduler is accessing an external data source but the credentials for this access have not been set. 

I would recommend you do the following: 

Verify the External Data Source used by the Mass Action Scheduler. 

Check whether the credential for this access is properly defined. 

Verify if the user scheduled for this process can access this credential. 

Re-authorize the external data source in case the credentials are expired. 

Finally verify the External Data Source → Authentication Settings to see if the proper permission has been granted. 

Once the credentials have been updated, please schedule the Mass Action. 

Hope this will help.

@Steve Pysnik

The issue is almost certainly that you swapped a Connected App for an External Client App, and that's where the chain breaks. External Client Apps and Connected Apps are different metadata types with different OAuth handshakes, and the Mass Action Scheduler package (last updated April 2022 and now archived) was built around the classic Connected App and Salesforce Auth Provider flow. When you authenticate the Named Credential against an External Client App, the OAuth callback can complete and the credential record gets created, but the package's Apex looks up the credential in a way that doesn't resolve it the same way, which surfaces as the "can't find the Named Credential" error even though the record exists in Setup. The package wiki's manual instructions explicitly walk through creating a classic Connected App, a Salesforce-type Auth Provider, and then the Named Credential authenticated against that provider, with no External Client App path anywhere in the flow. 

A couple of things worth checking and trying. First, Connected Apps are not actually fully blocked. What changed is that as of Winter '25 Salesforce restricts creating new Connected Apps by default, but admins can re-enable creation under Setup, then Connected Apps OAuth Usage, or via the "Allow creation of Connected Apps" permission. If you can turn that back on temporarily, the original Automated Setup wizard or the manual Connected App path will work exactly as the wiki documents, and that's still the most reliable route for this particular package. Second, if you do stay on the External Client App route, confirm your Named Credential URL is correct for a sandbox, since the wiki notes that for sandboxes the URL must point to the My Domain on .my.salesforce.com rather than .lightning.force.com

, and the legacy guidance even included the instance segment. A malformed URL or a credential whose Named Principal authentication silently failed will also throw a lookup-style error at config time. 

If neither lands it, given the package is archived and no longer maintained, the realistic long-term path is to confirm whether your org can re-enable Connected App creation (most can), use that, and treat the External Client App swap as unsupported for this tool. Worth flagging in the Mass Action Scheduler group that the Automated Setup button is now broken by the Connected App restriction, since that's a fix the maintainer or community would need to address, and you likely won't be the last to hit it. 

- SP