On the Acoustic Fingerpicking, step by step: Level 1 "Build your speed practice drill number #4" (https://www.guitartricks.com/lesson.php?input=12105&s_id=596), when you hit next you get Error encountered, this is an unpublished lesson.

If instead I choose the next lesson in the menu on the right, "Let's Slant the rhythm!" (https://www.guitartricks.com/lesson.php?input=12174&s_id=596). It does take me to that lesson.