Google recently implemented a security change and some of our pattern files hosted on Drive are currently accessible only by request.
If you come across a pattern with "request access," please let us know. You can name the designer & pattern in the comments of this post or email me at firstname.lastname@example.org and we will take it from there. You can also request access and the designer will know immediately and (hopefully) give you access asap.
It is possible we will lose some older patterns from inactive designers, but we will do our best to keep that from happening.
We did try to get in front of this, but even designers who opted out of the security change have had some pattern links changed. We know this is frustrating and we are doing our best to get things updated as quickly as possible.
Thank you for your patience and your understanding. We have hundred (if not thousands) of patterns at this point, created and hosted by dozens of designers, so this could take some time to sort out.