Error create subtask

[Tania Mata Morales]

I have a problem, a user cannot create subtasks because from the moment he clicks on create secondary incidents, it appears that something went wrong and he cannot create the subtask. It is worth mentioning that he has the role of administrator within the project.

[Nic Brough -Adaptavist-]

What is the behaviour when they click create sub-task?  Error message?  "can't create sub task" tells us nothing about the problem, it could be a large penguin sitting on the keyboard for all you've told us!