When using the Salesforce Google Drive integration with Conga Composer Templates, users receive an error message saying "Template ID does not exist and will be omitted."
What to Do
If using a Google Doc as your template, you must download the template in a Microsoft Office file format (such as .docx) before uploading to Salesforce. Do NOT upload the document using the Google Doc button that is part of Salesforce Google Drive integration. You can convert back to a Google Doc post-merge using the &DS7=19 parameter.