https://commons.wikimedia.org/wiki/Commons:Village_pump/Technical#Mass_upload_tools_login_problem
Multiple users have reported being unable to log in to various Commons upload tools such as Pattypan, Commonist, and VicunaUploader. I have tried Pattypan and can confirm that it works normally until the login stage, where it comes back with "Login failed". As I have 2FA enabled on my account, I am using an API password, as described in these instructions: https://commons.wikimedia.org/wiki/Commons:Pattypan/Two-factor_authentication.
Since multiple independent tools are failing, this appears to be a problem with the Wikimedia API rather than with any individual tool.