AWS CloudShell not working after creating a new account with Control Tower

Question

I have created a new testing AWS account in my organization with Control Tower, a new user was assigned to the new account with IAM Identity Center, and as I'm using this account to run testing, so my user has been assigned with an explicit full permissions policy like the following:

        {
            "Sid": "FullAccess",
            "Effect": "Allow",
            "Action": "*",
            "Resource": "*"
        }

Even though, when I log in to the new account with the user, I'm getting the following error when trying to use the AWS CloudShell:

Unable to start the environment. To retry, refresh the browser or restart by selecting Actions, Restart AWS CloudShell. System error: Environment was in state: CREATION_FAILED. Expected environment to be in state: RUNNING. To retry, refresh the browser or restart by selecting Actions, Restart AWS CloudShell.

I have tried changing policy, adding an inline policy, creating a new AWS account, synchronizing my local time with an NTP server, and all the other suggestions on this Stack Overflow post, but I'm still having the same issue.

Any idea or additional suggestion that could help me to find a solution to this issue?