Please check the value of:
string fileName = Limilabs.Mail.Licensing.LicenseHelper.GetLicensePath();
You can also easily test if license was loaded properly:
LicenseStatus status = Limilabs.Mail.Licensing.LicenseHelper.GetLicenseStatus();
if (status != Limilabs.Licensing.LicenseStatus.Valid)
{
throw new Exception(
string.Format("License is not valid: {0} ({1}).", status, fileName));
}