Please note there is no need to uninstall the Skype app. Simply force quitting the app will resolve any issues with Skype. Obviously if Skype is saying you entered the wrong credentials, then you entered the wrong credentials lol. 1.) hold the power down on the device until the slide to turn off screen appears, letting to of the power button. 2.) hold down the home button on the device until the Skype app closes and returns you to the main menu home screen. 3.) relaunch Skype and begin signing in. You should have success.
The power button is the sleep on off switch located on the upper right of the iPad Devi. The button that turns the screen on or off. The home button is the button located below the screen when in portrait view, the button that you click to get back to your apps, which is called your home screen. Does that help you understand the solutions better?