That error message can only really be caused by an outdated version of the PHP intl extension. But if you are really using PHP 7.1, this can’t be the case. Also strange that it doesn’t happen with the langkit.
Ok @texnixe, if I force SSL and deactivate language detection, the error doesn’t appear, excepting when I send the contact form.
The strange thing is that is not necessary to do it with langkit on the same server. It seems as something is not fine in my code but I don’t find it.
Moreover, I can’t access the panel, both with my site and langkit, it redirects me to https://panel/login. It’s the first time I see this problem.
The problem is that without knowing what might be causing this issue it might not get fixed. Have you tried or could you try with version 2.5.6 as well?
Hello, I discovered the same error when I updated from 2.5.6 to 2.5.7. The PHP version at our webhoster Strato is set to 7 but at the moment I don’t know which version is exactly used.
In version 2.5.6 the error doesn’t appear.