Steps to reproduce
- Create a project name 'Test'
- Create a custom field type Select List name 'Atlassian'
- Add a few options in it such as 'JIRA', 'Confluence'
- Create a new issue type 'Bug' with and select 'JIRA' for custom field 'Atlassian'
- Create an XML backup
- Delete the project 'Test'
- Edit the Configuration of the custom field 'Atlassian' so that it is limited to the Issue Type 'Bug' only
- Restore the project 'Test' by using Project Import
- There will be an error during the validation:
Edit the configuration of the custom field 'Atlassian' so that there is no restriction for Issue Type (All Issue Type selected)
Administration -> Fields -> Configure (the gear on the right of a custom field) -> Edit Configuration for Applicable contexts for scheme -> Issue Types -> "All issue type" option.
Some users have also experienced similar errors when importing custom fields due to trailing white space in custom field names. If you're getting a similar error, double check that your Custom Field names align exactly between the two instances.