Error EndUploadSingle - folder or file contains invalid characters.

I upload a file and I get an error:

EndUploadSingle{"Id":""}The file or folder name "KanBoDoc/FOLDERNAME" contains invalid characters. Please use a different name. Common invalid characters include the following: # % & * : < > ? / { | }

The problem you have encountered is rather clear. Since we are using SharePoint to store files it has some restrictions in regards to file names. Your file or file path contains invalid characters. Please change the name of the file or the path and try again.

Please see also these links:

https://support.office.com/en-us/article/Invalid-characters-in-file-or-folder-names-or-invalid-file-types-in-OneDrive-for-Business-64883a5d-228e-48f5-b3d2-eb39e07630fa

http://www.c-sharpcorner.com/UploadFile/54472d/sharepoint-limitations-for-naming-convention/

In KanBo 2.6 or higher versions, you will be alerted by KanBo to change your file name.