Configure a Slack Agent in Salesforce challenge- We can't find the action Create a Slack Canvas added to the TH Product Specialist agent

I'm trying to complete the "Configure a Slack Agent in Salesforce challenge" as part of the Legend path. After following all the steps described in the challenge, I get this message.  

We can't find the action Create a Slack Canvas added to the TH Product Specialist agent. Ensure it's added to the agent and save your work.

However, when reviewing all the steps once again, the Create a Slack Canvas action is part of the TH product agent under Product Gaps as required. 

What could be causing this error?  

#Trailhead Challenges