Failed to import data from JSON using import wizard

[DYang]

I have some JSON files generated from Freshdesk issues. While using import wizard to import the files, the process started: 

But then it shows "None issues and projects imported" , and the log shows

---

2023-02-15 02:28:56,000 INFO - Import started by 62f13692b5b801a9aff086d5 using com.atlassian.jira.plugins.importer.sample.SampleDataBean
2023-02-15 02:28:56,021 INFO - ------------------------------
2023-02-15 02:28:56,021 INFO - Importing: Users
2023-02-15 02:28:56,021 INFO - ------------------------------
2023-02-15 02:28:56,021 INFO - Only new items will be imported
2023-02-15 02:28:56,029 INFO - 0 users associated with import. All of them imported as inactive, this can be changed after import in User Access step.
2023-02-15 02:28:56,029 INFO - ------------------------------
2023-02-15 02:28:56,029 INFO - Finished Importing : Users
2023-02-15 02:28:56,029 INFO - ------------------------------
2023-02-15 02:28:56,030 INFO - 0 users successfully created.
2023-02-15 02:28:56,034 INFO - Retrieving projects...
2023-02-15 02:28:56,055 INFO - ------------------------------
2023-02-15 02:28:56,055 INFO - Importing: Issues
2023-02-15 02:28:56,055 INFO - ------------------------------
2023-02-15 02:28:56,055 INFO - Only new items will be imported
2023-02-15 02:28:56,064 INFO - 0 issues successfully created
2023-02-15 02:28:56,068 INFO - ------------------------------
2023-02-15 02:28:56,068 INFO - Finished Importing : Issues
2023-02-15 02:28:56,068 INFO - ------------------------------
2023-02-15 02:28:56,079 INFO - ------------------------------
2023-02-15 02:28:56,079 INFO - Importing: Issue Links & Subtasks
2023-02-15 02:28:56,079 INFO - ------------------------------
2023-02-15 02:28:56,079 INFO - Only new items will be imported
2023-02-15 02:28:56,083 INFO - ------------------------------
2023-02-15 02:28:56,083 INFO - Finished Importing : Issue Links & Subtasks
2023-02-15 02:28:56,083 INFO - ------------------------------
2023-02-15 02:28:56,085 INFO - ------------------------------
2023-02-15 02:28:56,085 INFO - Importing: Issue remote links
2023-02-15 02:28:56,085 INFO - ------------------------------
2023-02-15 02:28:56,085 INFO - Only new items will be imported
2023-02-15 02:28:56,089 INFO - ------------------------------
2023-02-15 02:28:56,089 INFO - Finished Importing : Issue remote links
2023-02-15 02:28:56,089 INFO - ------------------------------

Where did it go wrong? Thanks.