This is not possible. Once checked and validated the license status stays valid.
You can use following code to check the status at startup, and throw immediately, if the status is not valid:
using Limilabs.Mail.Licensing;
...
LicenseStatus status = LicenseHelper.GetLicenseStatus();
if (status != LicenseStatus.Valid)
{
throw new Exception($"License is not valid: {status}.");
}