This thread is resolved. Here is a description of the problem and solution.
Problem: Client cannot access site, seeing this error: Fatal error: Uncaught InvalidArgumentException: element_id and type do not match for element_id:86 the database contains tax_language while this function was called with tax_nav_menu
Solution: Please be sure to make a full backup of your site and database.
Then, go to WPML -> Support -> Troubleshooting.
Look for 'Clean up' and click the following: - Clear the cache in WPML - Remove ghost entries from the translation tables - Fix element_type collation - Set language information
Then please do a manual update by following the steps here: https://wpml.org/faq/install-wpml/#updating-manually
Lastly, if the error message still shows up, access your database (you should be able to access this through your channel). Search for the element id that is showing in the error message in the wp_posts table and once you find it, try deleting that row. Then, activate a fresh download of WPML core plugin.
This is the technical support forum for WPML - the multilingual WordPress plugin.
Everyone can read, but only WPML clients can post here. WPML team is replying on the forum 6 days per week, 22 hours per day.