Challenge Not Completed Prompt - We can’t find the model OpenAI GPT 4 Omni Mini selected for the prompt template.

I am trying to complete this challenge, Create an Effective Prompt Template

. 

I keep getting this error,  

We can’t find the model OpenAI GPT 4 Omni Mini selected for the prompt template. 

Things I have tried already to resolve this:

• confirmed that I am in the correct dev org
• confirmed that the right model is selected
• have deleted my browser history and cache
• have selected a new model, saved, then deactivated, selected the correct model, saved and activated

#Trailhead Challenges