I experience the same Problem with EndNote X8 on Windows 10. I believe till yesterday it might have worked, since I have full text in some references with the same journals that don’t work right now.
for example:
Cordasco, F. A. und Bigliani, L. U. (1997). The rotator cuff. Large and massive tears. Technique of open repair. Orthop Clin North Am 28, 179-193.
or arthroscopy papers like:
Richards, D. P. und Burkhart, S. S. (2007). Arthroscopic debridement and capsular release for glenohumeral osteoarthritis. Arthroscopy 23, 1019-1022, doi: 10.1016/j.arthro.2006.11.016.
-> in these example FFT didn’t find anything but I could download the PDFs manualy.
Maybe it is a Problem on my side since I am not an experienced user. But I inserted an open URL path of my university in the preferences and I could automaticly download for example arthroscopy papers yesterday like:
Lo, I. K. und Burkhart, S. S. (2004). Arthroscopic repair of massive, contracted, immobile rotator cuff tears using single and double interval slides: technique and preliminary results. Arthroscopy 20, 22-33, doi: 10.1016/j.arthro.2003.11.013.