I found the issue... they files belonged to a person who was no longer with company and were deleted. NLM reflected they werent there Notebook Tools didn's see that error, but downloaded a null file.
Thank you for the update I will show the error message in the Notebook Tools soon
Here is the updated screenshot. When I look inside Notebook Tools, I can see the file... Cannot share the notebook unfortunately. So I downloaded the file from Notebook Tools and the files is empty... it seems they are zombie files...
Can you hover the error and which error message and try to upload again? If you can share the notebook please share to support@nlmtools.com I will double check Thank you
Updated in the version v1.9.8 It will show failed sources in the NLM Tools Extension