Help! Can't Log In with Operator Role After Locking Screen

Hello,
I’m going through the AMAZING online training and trying out everything I learn. I got stuck in the Platform section, specifically under Design > Security.

I enable the protection resource in one of the screens and assigned a Protect Resource permission to the Operation role. I've already created a user named Operator1 and assigned them the Operation role.

After logging out from the Admin user, I tried to log in in designer as Operator1 using the dedicated password, but I keep getting a "Login failed" message.

What am I missing? I can't skip this step. Please help!

NB: I was able to login into Gateway with the Operator1

edit: oops, I may have misunderstood, I read that as you have locked yourself out.