Adding more pages to Montenegrin Wikipedia (in the incubator) is impossible due to the error: "You are trying to create a page without a valid ISO 639-1 or -3 code..." (screenshots)
Montenegrin language has a valid ISO 639-3 code, check [https://en.wikipedia.org/wiki/ISO_639:c here] or [https://iso639-3.sil.org/code_tables/639/data/c here]. It is completely in line with[[ https://incubator.wikimedia.org/wiki/Incubator:ISO_639 | the requirements ]].
Also, there are already 1,968 articles with wp/cnr prefix.
It is possible to edit existing pages, but not to add a new one.
On the cnr talk page, other users were complaining about being unable to create new pages (a few last posts), and this has been happening for at least a year.
Try adding a page on https://incubator.wikimedia.org/wiki/Wp/cnr (with a new user?)
Test cases (all on Ubuntu 20.04.3)
- FF and my usual Wiki user
- Chrome and new Wiki account
- Brave without login
The URL related to screenshots above: https://incubator.wikimedia.org/w/index.php?title=Wp/cnr/Vuksan_Vuksanovi%C4%87&action=submit