diff --git a/src/gui_qt/main/management.py b/src/gui_qt/main/management.py
index f5a0cc7..ef2c4bc 100644
--- a/src/gui_qt/main/management.py
+++ b/src/gui_qt/main/management.py
@@ -449,13 +449,23 @@ class UpperManagement(QtCore.QObject):
                 # sets are not in active order but in order they first appeared in fit dialog
                 # iterate over order of set id in active order and access parameter inside loop
                 # instead of directly looping
-                list_ids = list(model_p['parameter'].keys())
-                set_order = [self.active_id.index(i) for i in list_ids]
+                try:
+                    list_ids = list(model_p['parameter'].keys())
+                    set_order = [self.active_id.index(i) for i in list_ids]
+                except ValueError as e:
+                    raise Exception('Getting order failed') from e
+
                 for pos in set_order:
                     set_id = list_ids[pos]
+                    try:
+                        data_i = self.data[set_id]
+                    except KeyError as e:
+                        raise KeyError(f'{set_id} not found') from e
 
-                    data_i = self.data[set_id]
-                    set_params = model_p['parameter'][set_id]
+                    try:
+                        set_params = model_p['parameter'][set_id]
+                    except KeyError as e:
+                        raise KeyError(f'No parameter found for {set_id}') from e
 
                     if we_option.lower() == 'deltay':
                         we = data_i.y_err**2
@@ -474,20 +484,26 @@ class UpperManagement(QtCore.QObject):
                     if fit_limits == 'none':
                         inside = slice(None)
                     elif fit_limits == 'x':
-                        x_lim, _ = self.graphs[self.current_graph].ranges
+                        x_lim, _ = self.graphs[self.current_graph].range
                         inside = np.where((_x >= x_lim[0]) & (_x <= x_lim[1]))
                     else:
                         inside = np.where((_x >= fit_limits[0]) & (_x <= fit_limits[1]))
-
-                    if isinstance(we, str):
-                        d = fit_d.Data(_x[inside], _y[inside], we=we, idx=set_id)
-                    else:
-                        d = fit_d.Data(_x[inside], _y[inside], we=we[inside], idx=set_id)
+                        
+                    try:
+                        if isinstance(we, str):
+                            d = fit_d.Data(_x[inside], _y[inside], we=we, idx=set_id)
+                        else:
+                            d = fit_d.Data(_x[inside], _y[inside], we=we[inside], idx=set_id)
+                    except Exception as e:
+                        raise Exception(f'Setting data failed for {set_id}')
 
                     d.set_model(m)
-                    d.set_parameter(set_params[0], var=model_p['var'],
-                                    lb=model_p['lb'], ub=model_p['ub'],
-                                    fun_kwargs=set_params[1])
+                    try:
+                        d.set_parameter(set_params[0], var=model_p['var'],
+                                        lb=model_p['lb'], ub=model_p['ub'],
+                                        fun_kwargs=set_params[1])
+                    except Exception as e:
+                        raise Exception('Setting parameter failed') from e
 
                     self.fitter.add_data(d)
 
@@ -504,7 +520,9 @@ class UpperManagement(QtCore.QObject):
             logger.error('Fit preparation failed', *e.args)
             QtWidgets.QMessageBox.warning(QtWidgets.QWidget(),
                                           'Fit prep failed',
-                                          f'Fit preparation failed with message\n{e.args}')
+                                          f'Fit preparation failed:\n'
+                                          'Message:\n'
+                                          f'{e.args}:\n')
             return False
 
     def start_fit(self):