I am getting a 'No internet connection' error while trying to upload files on Koofr, even though my internet connection is working. Why?

This error most commonly occurs for one of these two reasons aside from no internet connection:

files are locked by some other process on the system or
files contain illegal characters not supported by Koofr (like emojis, backslash, etc.).

If your internet connection is working, please check for locked files or rename them if they contain illegal characters.