Yes, there are some restrictions. It is best to avoid very long names. Most systems limit to 512 characters or less. Also, the following characters should not be used for names because they may cause the file transfer to fail:
When naming files or folders, do not leave a space at the end of the name because it will cause Aspera to skip over this item for transfer. If you receive an error message of a failed transfer check for the above illegal characters or an end space and remove them, then try the transfer again with the renamed files or folders.