Problem: The client was unable to translate "Add a coupon"string into French. Solution: Updating WooCommerce plugin to the latest version solved the issue automatically
Please note that this solution might be outdated or not applicable to your specific case. We highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If the issue persists, please open a new support ticket at WPML support forum.
