Prepare your Salesforce Org project issues

Hello everyone,

I am currently trying to complete the Project " Prepare your Salesforce Org for Users". I am up to the last step and have followed the instructions as accurately as possible by copying text where possible. However, when I go to verify the step the following message appears:

"Ensure that you are following all the instructions for posting to a Chatter group."

I believe my issue is related to placing a link within the post as directed at the end of the step, although I am unsure what I am doing wrong. I have tried creating new trailhead playgrounds, using the link indicated in the image, and several other things but the above message always appears.

Any help or suggestions would be appreciated.