Can't login after update

I just installed the last update of the plugin on multiple sites and… I can’t access my admin panel anymore, on any of them. At first I didn’t see anything was wrong, because I was connected to the admin panel. Without disconnecting, when I came back later, I discovered it disconnected me automaticaly. I wasn’t able to access the admin panel anymore (I can access login page, but even when providing username and password, I’m stuck on the login page).

Tried renaming the plugin folder, doesn’t work. Tried removing htaccess files (in the root and in the wp-admin folder), doesn’t work. Tried deleting cache and cookies of my browser, doesn’t work. Tried to put htaccess files from a backup, doesn’t work. For now I’m just hopping I won’t have to put back a bunch of backups. I’m worried ’cause I activate the bad login protection in the plugin, but can’t remerber the number of times I have before being ban… Sites themselves are working well.

Must say I use Bulletproof Security plugin too, I updated it too. So what can I do now? Please help me!

https://www.ads-software.com/extend/plugins/better-wp-security/