Imprt failes importing xliff file

Did you follow the instructions and duplicate the course, export the Cliff and then import into the new file?

Yes, I have duplicated the course, exported the xliff, translated and I was trying to import

You may need to raise a support case, it may be that the Xliff structure has been modified, it should just work if you follow the correct steps.

sure, where can I raise a support case?

Here if you don't have teams account https://articulate.com/360/contact-us?success_chat=true

here if you do https://articulate.com/support/contact/360-teams