I cant login apple id in my iphone4

The iPhone 4 does not support 2 factor authentication so you cannot login with your username and password. |

Instead, you will need to get a verification code from settings on another apple device. and log in with that code instead of your password. This helped me login to An old imac

Follow this steps to get your verification code

From your iPhone, iPad, or iPod touch

If your device is online:

1. Go to Settings > [your name].
2. Tap Password & Security > Get Verification Code.

If your device is offline:

1. Go to Settings > [your name].
2. Tap Password & Security. 
3. A message says "Account Details Unavailable." Tap Get Verification Code.

From your Mac

1. Go to Apple menu  > System Preferences, then click Apple ID.
2. Click Password & Security > Get Verification Code.