[Chiuso] Exporting translations from staging to production website

Background of the issue:
I want to move all the translations I have in the staging environment to a production website. My current plan is to translate everything in the staging environment and then enable the plugin on the production website to import everything.

Symptoms:
I tried to export the current translations as an XLIFF file and then import them, but I got an error message saying that those files do not belong to this system.

Questions:
How can I export and import translations from a staging environment to a production website using WPML?
Is it possible to translate everything in the staging environment and then import it to the production website?