A. 1. Verify your credentials: Double-check your email address and password for accuracy. Ensure that there are no typos or extra spaces. 2. Check your internet connection: Make sure you have a stable internet connection, as poor connectivity can lead to authentication failures. 3. Enable less secure apps: If you're using Gmail or similar services, you may need to allow access for less secure apps in your email account settings.

B. 4. Remove and re-add the account: Go to the app settings, remove the problematic email account, and then add it again to refresh the authentication process.