This error occurs when Composer is either unable to connect to your organization's Salesforce instance or the user launching the merge operation does not have sufficient visibility to objects or fields included in the Composer Managed Package.
What to do
There are a few things to check when you receive this message:
- Make sure all fields on the Conga Template are set to "visible" for any Profile running the solution (Setup > Create > Objects, click on then click on each custom field name and click and make sure all relevant profiles have the field "visible").
- Ensure “Lock Sessions to IP Address from which they originated” is disabled (Setup > Administration Setup > Security Controls > Session Settings).
- Verify that the Session Timeout value is at least 30 minutes.
- Ensure the Conga Composer URL contains an “&Id=” parameter and that it is set to a valid ID.
- Don’t try to “Preview” a Conga Composer button. You must click it from a Salesforce record.