Problem: The client was unable to add Dutch (Belgium) with the locale code 'nl_BE' to their WPML languages, receiving an error that the default locale already exists, despite it not being visible in the WPML > Languages > Add / Remove languages section. Solution: We recommended the client to check their database table
_icl_languages
for any entries with a default locale set to 'nl_BE'. Upon inspection, it was found that the locale should have been 'nl_NL'. The client corrected these values in their database, which resolved the issue and allowed them to add Dutch (Belgium) as a custom language.
If this solution does not apply to your case, or if it seems outdated, we highly recommend checking the related known issues, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If issues persist, please open a new support ticket.
