The link provided in Step 2 of Task 3 of this lab in the section called "Test the new version" is incorrect.
This is the link's URL:
http://ip172-18-0-9-bq7qj75im9m000e1aaug-8080.direct.labs.play-with-docker.com/
Seems like it should be port 80 not 8080
http://ip172-18-0-9-bq7qj75im9m000e1aaug-80.direct.labs.play-with-docker.com/