I cannot sign in to the App Store even though the username and password is correct

Hey annafromdurban,

Thanks for the question. If I understand correctly, you have a working Apple ID and password but you cannot sign into the App Store. I would recommend that you read this article, it may be able to help the issue.

Can't connect to the iTunes Store - Apple Support

If you can't connect to the iTunes Store on your iPhone, iPad, or iPod touch:

1. Make sure that your date, time, and time zone are correct. Tap Settings > General > Date & Time.
   Time Zone might list another city in your time zone.
2. Make sure that your iOS software is up to date. Tap Settings > General > Software Update or connect your iOS device to iTunes and click Check for Update
   on your device's Summary page.
3. Check and verify that you're in range of a Wi-Fi router or base station. If you're using cellular service, make sure that cellular data is turned on from Settings > Cellular.
   If you're connected to cellular data, larger items might not download. You might need to connect to Wi-Fi to download apps, videos, and podcasts.
4. Make sure that you have an active Internet connection. Check your device's user guide for help with Internet connection.
5. Check to see if other devices, such as portable computers, are able to connect to the Wi-Fi network and access the Internet.
6. Reset (turn off and then on again) your Wi-Fi router.

If there's still an issue, learn what to do if your device won't connect to a Wi-Fi network.

Thanks for using Apple Support Communities.

Have a good one,

Mario