Seeing any of these screens for more than 5 minutes potentially indicates an issue in your browser or network connection:
There are several issues that can keep the lab console from loading in addition to client connection challenges.
Stale session cookies in your browser. Try clearing all vmware.com cookies or use a different browser. (Even a private/incognito browser session may not work.) Login again after clearing vmware.com cookies and resume your lab.
Network web proxy/firewall. Try a different network or whitelist vmware.com.
Active VPN. (Exit any active VPN.)
Other streaming activity. Exit other streaming applications.
Overloaded WiFi network. Use a hard-wired Ethernet connection.
As a last resort, end your lab and re-enroll and start again.