Status "not checked" means that GetProspect hasn't searched for an email address for this contact yet. The most common reason for that is the lack of credits on your account or technical issue.
To check how many credits you have, click on the account icon in the right upper corner.
You can upgrade your plan in the Plan and Billing section of your account.
In case if you have enough credits, but still have Not checked emails added, you can select them and press Find Email command to process the email search for them