Hi,
Before importing the products with characteristics, you must already have the characteristics created in the menu Products>Characteristics and they need to have all the values filled in.
If that's not the case, please do it.
Also, in your CSV, the main products need to have the default value of the characteristic entered in the characteristic column, so make sure that it is the case.
Finally, it could be a problem with the fact that the characteristic names use special characters. Try to use the alias of the characteristics instead of their name and make sure that the alias do not contain any special characters and that could also help.