Error on Linking Issue Parents to their subtasks

[Jael Palmeiro de Carvalho]

Hey, I just posted a question on this last Friday (21) named "Error finding the Parent ID", the answers that you guys gave me solved my problem.
But now after the import, the tasks and subtasks don't get linked on their parent issues, I did the test with 2 parent issues and 5/6 tasks each and it's all good, but when I try 300 it just don't work, any help I could get? 

[Trudy Claspill]

Hello @Jael Palmeiro de Carvalho 

When you post a question that is related to another question, it is helpful if you provide a link to that other question. For the benefit of others, I assume you mean this one:

https://community.atlassian.com/t5/Jira-Work-Management-Questions/Error-finding-the-Parent-ID/qaq-p/2512111

When you say the "tasks and subtasks" don't get linked to their parent issues, what exactly do you mean?

In Jira the issue hierarchy is

Epic
|-- standard level issue types; i.e. Story, Bug, Task
    |-- subtask level issue types; i.e. Sub-task

Do the sub-tasks get linked to their parent issue at the standard level?

Do the issues you are importing at the standard level get linked to their Epics?

Are you importing issues to a Team Managed project or a Company Managed project?

Can you provide several rows of sample data similar to what you have in your CSV file that illustrates the different types of issues you are trying to import, and point out which columns you are using to specify the parent of an issue?

Do the parent issues in all cases already exist in Jira before the import process is started, or are you trying to create parent issues and child issues during a single import process?