Another try to fix JSON issues.

web/pgadmin/utils/ajax.py

@@ -26,7 +26,8 @@ class DataTypeJSONEncoder(json.JSONEncoder):
             return (datetime.datetime.min + obj).time().isoformat()
         if isinstance(obj, decimal.Decimal):
             return float(obj)
-
+        if isinstance(obj, bytes):
+            return obj.decode('utf-8')
         try:
             retval = json.JSONEncoder.default(self, obj)
         except TypeError:

web/pgadmin/utils/driver/psycopg2/connection.py

@@ -1987,6 +1987,8 @@ Failed to reset the connection to the server due to following error:
 
             if parameters:
                 mogrified_sql = cursor.mogrify(query, parameters)
+                if isinstance(mogrified_sql, bytes):
+                    mogrified_sql = mogrified_sql.decode(self.python_encoding)
                 return mogrified_sql
             else:
                 return query