Lumen to laravel upgrade - laravel passport user passwords

So I've been working on a project which consisted of moving a lumen framework to Laravel. I've succeeded with this but I'm having an issue with deploying the application.

I've upgraded and got Lumen passport converted to Laravel passport. The issue I'm having now is that when users try to log in. There passwords are now invalid.

Has anyone encountered this issue and if you did. What steps did you take the rectify the situation?