If you have a survey on your account that is displaying as Locked.

This survey was created with features and/or question types that are not supported by the plan you are currently subscribed to. You will not be able to edit this survey until you upgrade to a plan which contains all of the features used by this survey.

Hovering your cursor over the Survey Name will display a message indicating the minimum plan needed to unlock the survey.

To unlock the survey, you will need to upgrade to the plan level indicated in the message or higher.