If you use the multilingual plugin WPML and you set up the language settings to use custom folders with the language code in it, e.g. yourdomain.com/en/ you may run into an issue where opening a page on a staging site results in an error 404. This can happen when the staging sites permalinks are disabled.
There are three possible solutions:
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Create the staging site in a subdomain
You can clone your WordPress website to a subdomain. If you do this you will not run into any link structure issues anymore as the URL structure will be exactly mimicked as it is on the production website.
Change WPML language URL format
You can switch the WPML language settings on your WP Staging staging site to URL based language like yourdomain.com/lang=en?
You can do this under WPML > Languages
Note: If you push the staging site back to live you will need to revert this setting on the live site.
Activate post name permalinks
You can try to activate post name permalinks on the staging site by following this article.