Summary

Creating a Space return 'Invalid Space key: null'

How to replicate

1. Create a project in JIRA. Please make sure that you create Confluence Space as well while creating JIRA project.
2. Go to Confluence and create a Software Project Space and then put the project that just created in JIRA.
3. Change the Space Key.
4. It will return the error Invalid Space key: null

Actual Result

The Space will not be created and will return Invalid Space key: null.

Expected Result

The Space will be created.

Workaround

Clear Confluence plugin caches and restart application.