There are two ways to reset admin password:
Connect to website via SSH, go to your website root folder (public_html) and enter command
php artisan october:passwd admin (where admin is user name).
After that you can enter own password or use automatically generated password proposed by CMS.
Open phpmyadmin, select database, open
backend_users table, find your user and replace hash in password field to: $2y$10$CtnXkR432BDurG1kpyUgZO4.soq5xYGa.8KGG9Fan9Fh9kH3PFIAe
After that you can login in backend using your user name and "password" as password.