How do I fix editing issue on Business package

Our company has the SmartSheet Business Package.

As I understand this package has unlimited free editiors.

We have been running our timesheet system off Smartsheet for some time but from last week the users with a free licence who have Editor - can share/ Editor cannot share access to both the underlying sheet and report view are unable to add their information.

They get an error message to say the cell is locked. No changes have been made on our side.

Can anyone suggest away to overcome this. We don't want them to have admin access to ensure the underlying sheet is kept sound.

Ive attached some screenshots to display settings and error message displayed.