A. 1. Double-check that you are entering the correct password, paying attention to case sensitivity and any special characters. 2. If you are unsure, use the 'Forgot Password' feature to reset your password and try logging in again.

B. 1. Clear the app's cache as mentioned previously, then try logging in again. 2. If the problem continues, try logging in from a different device to see if the issue is specific to your iPhone.