correct username and password not accepted Apple ID macbook

I'm using the correct username and password but it won't let me sign in to my Macbook Air M2. I had the same problem with my ipadair2. I changed my password, I changed my username. Both devices appear on my manage my apple ID page. On the ipad, I was able to workaround by signing in to the app store instead. On my Mac it works for the app store too but doesn't allow me to set up icloud and keeps saying my username and password is incorrect - can anyone help?