Can not create sub task

[FakhruddinAbdi]

Starting from yesterday, i can not create sub task.

The error is attached

Anyone can help?

[Daniel Ebers · Accepted solution]

Hi FakhruddinAbdi,

did this happen at once or have there been changes in your Jira?
I am thinking of any configuration chance you probably made (or a second admin of your Jira)?

Is it new "new issue view" of a classic project you are viewing - if so, can you switch back to the old issue view?

Here is a thread where this problem also showed up - along with some information and debug.
In case this does not help please provide further details.

Cheers,
Daniel

[FakhruddinAbdi]

Thanks to @Daniel Ebers 

Following your suggestion about change to the old issue view, I saw the actual error message, which was about the default assignee issue.

Recently, I have removed the project lead person from Jira and it was set to default assignee, system couldn't create a new subtask

I just changed the project lead and it fixed.