Unable to sync because the folder name is invalid.

Hi,

I use Cleative Cloud Files Folder for external storage on macOS 10.15.3, but I can use it without any problem.
You can use a space in the folder name, but be careful if there is a space at the end, because you will not be able to sync.
In this screenshot, there are two "Aroflo Frooty Tipping 2019" folders, but the folder below has a space at the end.

In your screenshot, note that the compressed file name is "Aroflo Frooty Tipping 2019 .Zip".

The article states that the last space is fine for Macs.
In the case of external storage, the situation is different and problems may arise.

https://helpx.adobe.com/creative-cloud/kb/arent-my-files-syncing.html#id_96315

Remove trailing characters

Try renaming your folders without any spaces or special characters. 

On the web, underscores_ and hyphens- are acceptable but not spaces.

     my_folder_name

     my-folder-name