Could not Sign into app store but I can sign into ICloud?

I recently changed my apple ID, and login details, I remember them but when I go to login to my app store the following error message reads "Could Not Sign In"

Now, I can login to my ICloud but when I go to turn on Media and Purchases another error reads "Could Not Sign In Authentication Failed"

I am using an IPhone 12 Mini and have searched all over the internet for a solution but have found nothing, anyone with any ideas on how to fix this?

Thanks