I completed all the below steps in the challenge 
1. Create a new public Chatter group called 'General Product Feedback'.
2. Ensure your Chatter group has a description. Adding a photo is also recommended, but this will not be tested.
3. Add at least one additional user to the group (this may require you to create a new user if there isn't already a second Chatter-capable user in your organization).
4. Make a first post to your new group and give it the topic 'Happy Customer' ('HappyCustomer' is also acceptable).
5. Add values to your Chatter profile 'Title', 'About Me', and 'City' fields. Add a Chatter profile picture if you've not done so already.

But it keeps giving me the below error when i validate the challenge. Please help. 

​Challenge Not yet complete... here's what's wrong: 
The topic 'Happy Customer' was not created. Please make another post with this topic or add it to your existing post.
 

I completed all the below steps in the challenge 
1. Create a new public Chatter group called 'General Product Feedback'.
2. Ensure your Chatter group has a description. Adding a photo is also recommended, but this will not be tested.
3. Add at least one additional user to the group (this may require you to create a new user if there isn't already a second Chatter-capable user in your organization).
4. Make a first post to your new group and give it the topic 'Happy Customer' ('HappyCustomer' is also acceptable).
5. Add values to your Chatter profile 'Title', 'About Me', and 'City' fields. Add a Chatter profile picture if you've not done so already.

But it keeps giving me the below error when i validate the challenge. Please help. 

​Challenge Not yet complete... here's what's wrong: 
The topic 'Happy Customer' was not created. Please make another post with this topic or add it to your existing post.