diff --git a/tanner/api/api.py b/tanner/api/api.py
index 46b09f44..acab5912 100644
--- a/tanner/api/api.py
+++ b/tanner/api/api.py
@@ -43,7 +43,7 @@ async def return_snare_info(self, uuid, count=-1):
         query_res = []
         try:
             query_res = await self.redis_client.zrevrangebyscore(
-                uuid, offset=0, count=count
+                uuid, offset=0, count=count, encoding='utf-8'
             )
         except aioredis.ProtocolError as connection_error:
             self.logger.error('Can not connect to redis %s', connection_error)
diff --git a/tanner/session_analyzer.py b/tanner/session_analyzer.py
index 96b4c72a..5bbb04fc 100644
--- a/tanner/session_analyzer.py
+++ b/tanner/session_analyzer.py
@@ -19,8 +19,7 @@ async def analyze(self, session_key, redis_client):
         session = None
         await asyncio.sleep(1, loop=self._loop)
         try:
-            session = await redis_client.execute('get', session_key)
-            session = json.loads(session)
+            session = await redis_client.get(session_key, encoding='utf-8')
         except (aioredis.ProtocolError, TypeError, ValueError) as error:
             self.logger.error('Can\'t get session for analyze: %s', error)
         else:
@@ -143,16 +142,17 @@ async def detect_crawler(self, stats, bots_owner, crawler_hosts):
         if stats['requests_in_second'] > 10:
             if stats['referer'] is not None:
                 return (0.0, 0.5)
-            if stats['user_agent'] in bots_owner:
+            if stats['user_agent'] is not None and stats['user_agent'] in bots_owner:
                 return (0.85, 0.15)
             return (0.5, 0.85)
-        if stats['user_agent'] in bots_owner:
+        if stats['user_agent'] is not None and stats['user_agent'] in bots_owner:
             hostname, _, _ = await self._loop.run_in_executor(
                 None, socket.gethostbyaddr, stats['peer_ip']
             )
-            for crawler_host in crawler_hosts:
-                if crawler_host in hostname:
-                    return (0.75, 0.15)
+            if hostname is not None:
+                for crawler_host in crawler_hosts:
+                    if crawler_host in hostname:
+                        return (0.75, 0.15)
             return (0.25, 0.15)
         return (0.0, 0.0)
 
@@ -161,13 +161,14 @@ async def detect_attacker(self, stats, bots_owner, crawler_hosts, attacks):
             return 1.0
         if stats['requests_in_second'] > 10:
             return 0.0
-        if stats['user_agent'] in bots_owner:
+        if stats['user_agent'] is not None and stats['user_agent'] in bots_owner:
             hostname, _, _ = await self._loop.run_in_executor(
                 None, socket.gethostbyaddr, stats['peer_ip']
             )
-            for crawler_host in crawler_hosts:
-                if crawler_host in hostname:
-                    return 0.25
+            if hostname is not None:
+                for crawler_host in crawler_hosts:
+                    if crawler_host in hostname:
+                        return 0.25
             return 0.75
         if stats['hidden_links'] > 0:
             return 0.5