Hi Alimir,
I’m having this same problem, and I think this could be related to the use of, in my case in particular, Polylang multilingual plugin.
I have noticed different behaviors when trying to use the Bootmodal login in different languages.
The default language on my site takes me to /login, which shows the wordpress login page, but without the wordpress logo.
When using the bootmodal login in other languages, I get directed to, for example, /en/login, and this shows me a 404 page.
I think this could be related with permalinks structures, and being also affected by how the Polylang plugin is impacting the way the permalinks work.
Any help will be much appreciated.
Thanks!
