So, you cannot login to your STARZ app because you encountered the error ‘Incorrect Email or Password.’ It happens to several users and there are also different reasons why this issue occurs.

It can be that you have indeed entered a wrong email or password hence you see the error message. Another possible cause of the problem is your VPN connection, if ever you are using one to stream on STARZ streaming service. There can be various possibilities, but let’s jump to the possible solutions to fix the issue.
Methods to Help You Fix Login Error Incorrect Email or Password on STARZ App

If you have entered a wrong email address or password, you can try again. But, this time, make sure to double check or verify that you typed the correct credentials before clicking the Sign in button.
In the event that your current login details are correct but STARZ tells you that they are wrong, what you can do is to reset your password. Doing so will allow you to create a new password, so you can try logging in again with the new details.
How do you reset your STARZ password? Go to starz.com/us/en/login/forgot-password. Enter your email address and check the box indicating that you are not a robot. Click Send Link. Open your email and follow the instructions on how you can reset your password.
Clearing the STARZ app cache and data also helps in resolving not just login issues but other errors as well. Just head over to the app section of your device and look for STARZ. Go to Storage and select Clear Cache and Clear Data.
Are you using a VPN server? It may be blocking you from accessing the app. Turn off your proxy connection before you login again.
Take note that if you subscribed to STARZ via your cable or TV provider, you may need to login your provider details. Select Log in with TV Providers and choose your provider. You should login using the details you used with your TV provider.
In Summary
Login issues can be caused by different things. The important thing is for you to identify these causes and work on their specific solutions so you can get back on your streaming.