[Risolto] Translation is not showing

I am reopening this issue, as the problem is still occurring.

My website is originally in English, and I translated it using WPML into Spanish and Dutch (I still need to add the French translation).
I completed 100% of the translation work and clicked Save and Complete. However, only the Dutch translation is displaying correctly. When I select Spanish from the footer, it takes me to the Spanish version of the site, but the content is still shown in English.

So far, I have already:
Increased the memory limit to 256 MB
Unregistered the site
Uninstalled and reinstalled the plugin
Cleared the site cache

Unfortunately, none of these steps resolved the issue.