Your PubGuru header bidding script is not loading and therefore, no Header Bidding auction can take place.
Step 2: Under Access & Authorization, check that you have firstname.lastname@example.org & email@example.com added as Administrator
Step 3: Re-check the header bidding tags deployed on page for any typos
Step 4: Audit your header bidding configuration for accuracy
Step 5: Fix all other errors in PubGuru Ad Inspector (PGAI)
Step 6: If the error persists, contact firstname.lastname@example.org