diff --git a/README.md b/README.md
index 62babb5e3a03f9943a2ec84d208822fb7868d3e1..1e2f590b15f85b16203aab4a836a52042d3b3b12 100644
--- a/README.md
+++ b/README.md
@@ -114,7 +114,7 @@ Here there is a compilation of some tips that could be usefull to solve some err
     ```
 
     4. Is *ssh* installed on both computers? 
-    Run the following command to install ir:
+    Run the following command to install it:
 
     ```bash
     sudo apt update && sudo apt upgrade && sudo apt install ssh
@@ -139,15 +139,23 @@ or
 or
 
 * **I can't call any service or action:**
+    1. First at all check that the topic/service/action exists. On the same terminal where your command is not working:
+    ```bash
+    rostopic list
+    ```
+    or
+    ```bash
+    rosservice list
+    ```
+    In case that the topic/srvice/action doesn't exist chek if there is another one similar and change it to match with the listed one. If no topic or service is listed, probably it will be a ROS network problem.
 
-    Probably it will be a ROS network problem
-    1. Is from another computer? Are both computers on the same network?
-    2. Is from another computer? Is the ROS network properly configured?
+    2. Is from another computer? Are both computers on the same network?
+    3. Is from another computer? Is the ROS network properly configured?
     Check that you have followed the steps on [ROS network configuration](https://gitlab.iri.upc.edu/mobile_robotics/adc/platforms/model_car/iri_model_car_how_to/-/blob/master/doc/real_model_car.md#bring-up) paying atention that the ip adresses used are the correct ones.
-    3. If not resolved test it on the onboard computer.
+    4. If not resolved test it on the onboard computer.
     Connect all the necessary devices (keyboard, mouse and display) to the car an test that the problem is solved. In this case it was a network problem. Please check another time that the ROS network configuration is properly set with the correct ip addresses.
-    4. If not resolved try to search the error on google. Sometimes this is very useful.
-    5. Contact the support staff.
+    5. If not resolved try to search the error on google. Sometimes this is very useful.
+    6. Contact the support staff.
 
 * **The motors don't work:**