PHP preg_match not giving me the expected result

Question

I have to check if a string matches bio control numbers for products. This link has the specifications (unfortunatly in german).

The numbers start with a country-code, followed by 3 characters and two or three digits. Here some examples:

DE-ÖKO-233
IT-BIO-053
DK-ØKO-79

---

This is the regex, I came up with: /[A-Z]{2}-[A-ZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŒŠŸ]{3}-\d{2,3}/

While it works perfectly fine on regex101.com, it doesn't work in my php-script as it returns an empty array.

$value = "DE-ÖKO-007";

preg_match('/[A-Z]{2}-[A-ZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŒŠŸ]{3}-\d{2,3}/', $value, $matches);

print_r($matches);

---

My expected output would be

Array(
    [0] => "DE-ÖKO-007"
)

but I actually get

Array(
)

Am I missing something in the way preg_match works?