web api query - 401 error

Dear all,
 
When I call 'api/values', it only allows me login as 'full' user details, but if a login as 'trial' user login details, it throws a 401 error. I would like to ask, if I am missing something in the queries in the user class below or the basicAuthn class:

protectedoverride Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            AuthenticationHeaderValue authValue = request.Headers.Authorization;
 
            if (authValue == null || authValue.Scheme != BasicAuthResponseHeaderValue)
            {
                return Unauthorized(request);
            }
 
            string[] credentials = Encoding.ASCII.GetString(Convert.FromBase64String(authValue.Parameter)).Split(new[] { ':' });
            if (credentials.Length != 2 || string.IsNullOrEmpty(credentials[0]) || string.IsNullOrEmpty(credentials[1]))
            {
                //return Unauthorized(request);
var resp = new HttpResponseMessage(HttpStatusCode.NotFound)
                {
                    Content = new StringContent(string.Format("access denied")),
                };
            }
 
            ClaimRole user = repository.trial(credentials[0], credentials[1]);
			ClaimRole user2 = repository.unlim(credentials[0], credentials[1]);
 
                if (user == null || user2  == null)
            {
                var resp = new HttpResponseMessage(HttpStatusCode.NotFound)
                {
                    Content = new StringContent(string.Format("access denied")),
                };
 
            }
            else
            {
 
               IPrincipal principal = new GenericPrincipal(new GenericIdentity(user.Username, BasicAuthResponseHeaderValue), newstring[] { user.role });
                Thread.CurrentPrincipal = principal;
                HttpContext.Current.User = principal;
            }
 
            returnbase.SendAsync(request, cancellationToken);
 
        }

User Class

public ClaimRole trial(string username, string password)
        {
            var query = (from s in db.subs
                        join u in db.user on s.sUID equals u.uID
                        where s.sExpiryDate >= DateTime.Now &&
                        u.uUsername == username &&
                        u.uPassword == password
                        select u).FirstOrDefault();
 
            if (query != null)
            {
                // Build a user and add the appropriate Trial role
returnnew ClaimRole { Username = query.uUsername, Password = query.uPassword, role = "Trial" };
            }
            else
            {
                // No user was found
returnnull;
            }
        }
 
        public ClaimRole full(string username, string password)
        {
            var query = (from s in db.subs
                        join u in db.user on s.sUID equals u.uID
                        where s.sPID.Value == 163&&
                        u.uUsername == username &&
                        u.uPassword == password
                        select u).FirstOrDefault();
 
            if (query != null)
            {
                // Build a user and add the appropriate Trial role
returnnew ClaimRole { Username = query.uUsername, Password = query.uPassword, role = "full" };
            }
            else
            {
                // No user was found
returnnull;
            }
        }

 
Please advise
many thanks