Not able to import many fields with Zephyr Importer

I've tried importing some of the default Jira fields but no luck on getting them into Jira. For example, assignee, fix version, epic, component, and link issues.

The only thing worked for me is the test steps and expected results.

I believe I've mapped everything correctly as shown in the screenshot.

What could possibly be the reason why I can't import any field besides summary, test steps, and expected results?