Hello everyone,
Thank you again for sharing the issues with accessing public preview. We apologize for the inconvenience and appreciate your patience. Here’s an update:
After investigating, we found a bug impacting the rollout. Public Preview for the new Planner should have been enabled in two paths: 1) via Teams Admin Center (known as “Public Preview for Microsoft Teams”), and 2) via M365 Admin Center (known as “Targeted Release”). The bug is impacting path #1. That’s why some of you (the large majority) are seeing the new Planner preview and were able to use it and provide feedback, while others couldn't. We are working on a fix, but because it is not a trivial one, we do not have an ETA yet. In the meantime, as mentioned, the new Planner Preview is available via method #2 (admin instructions in this article).
We will update the blog to reflect this know issue, and keep you updated once it’s fixed.
Your reports were incredibly valuable in catching this issue, thank you!
Biatrice Ambrosa and Roberto_Bojorquez, on behalf of the team