Scheduling mode (period mode) not found among options available in select field
Verify the settings of the task mode custom field (Jira Admin permissions needed).
Go to Jira Administration > Issues
Select Custom fields on the left.
Find the task mode field
Go to Actions > Configure
Verify the following settings
Go to Edit Options
make sure all four period modes are listed and enabled.Change applicable contexts for the scheme.
Ensure the fields are available for all issue types and the context is global.