This issue has been resolved at Dec. 10th, 8:45 pm JST.
One of the servers cause the trouble and many users could not download/upload the files.
We detect the server and cut it out from our network.
We sincerely apologize for any inconvenience caused.
Currently Dec 10th 2018 10:00 a.m. JST, all SkyDesk services cause errors for any file operations.
1. SkyDesk Mail : Attach files to send mail
2. SkyDesk CRM: Export PDF, attach files to records
3. SkyDesk Cards R: Create a new contact from card images
4. Any other file related operations in all services.
We are working on it as a top priority.
We sincerely apologize for any inconvinience caused.