"XML loaded is missing letter type Tag" when testing via "Notification Template"

Question

How to resolve the error "XML loaded is missing letter type Tag", when using "Notification Template"?

This tool is found in: ADMINISTRATION > General Configuration > Configuration Menu.

Answer

A step was missing when loading and testing the XML for Letter Customization.

The workflow is:

1. Go to: General Configuration Menu

2. Click the Notification Template
3. Click: XML to Upload

4. Find the XML file
5. Click: Save

At this stage, the upload is confirmed by Alma, and the Letter Type is displayed: https://www.screencast.com/t/Cma4ppKmnX4n

6. Proceed, e.g. by clicking: Send by email
7. Fill-in your email address
8. Click: Run XSL

Instead of emailing, it is possible to view results on the screen, by skipping steps #6-7.

More Information

1. "How To" documentation can be found at:

https://knowledge.exlibrisgroup.com/Alma/Product_Materials/Overview_Materials/Presentations_and_Documents#Letters

2. Screenshots regarding the process mentioned in this article are found in step FIVE, second screenshot, at: 

https://knowledge.exlibrisgroup.com/@api/deki/files/42067/Letters_-_How_to_preview_configuration_changes_to_the_xsl_of_an_Alma_letter_without_actually_sending_it.docx

3. Customers asked for examples for such letters. This exists in: https://developers.exlibrisgroup.com/blog/Alma-letters-XML-samples-for-working-on-XSL-customization