diff --git a/localization_log_gamma_model.py b/localization_log_gamma_model.py
index b4ea53f..a991895 100644
--- a/localization_log_gamma_model.py
+++ b/localization_log_gamma_model.py
@@ -55,16 +55,19 @@ def fittingSingle(filepath, args):
     best_env_gamma = None
     best_rsses = None
     for i in range(args.iternum):
-        result = modelfit_log_gamma(
-            rx_locs,
-            rx_rsses,
-            bounds_pwr=(-60, 0),
-            bounds_gamma=(2, 6),
-            bounds_loc_x=(0, 6.4),
-            bounds_loc_y=(0, 6.4),
-            monte_carlo_sampling=args.montecarlo,
-            monte_carlo_sampling_rate=args.montecarlo_rate
-        )
+        try:
+            result = modelfit_log_gamma(
+                rx_locs,
+                rx_rsses,
+                bounds_pwr=(-60, 0),
+                bounds_gamma=(2, 6),
+                bounds_loc_x=(0, 6.4),
+                bounds_loc_y=(0, 6.4),
+                monte_carlo_sampling=args.montecarlo,
+                monte_carlo_sampling_rate=args.montecarlo_rate
+            )
+        except RuntimeError:
+            continue
         # unpack
         fit_mse, est_tx_loc, est_tx_pwr, est_env_gamma, est_rsses = result
         if fit_mse < min_fit_mse:
@@ -75,6 +78,9 @@ def fittingSingle(filepath, args):
             best_env_gamma = est_env_gamma
             best_rsses = est_rsses
 
+    if best_tx_loc is None:
+        return
+    
     # calculate diff
     data_best_est = convert_vector_to_mat(rx_locs, best_rsses, data.shape)
     data_diff = data - data_best_est