Does your Yahoo mail account password is not working on iPhone? Then probably, you have changed the password on a web browser and forget to update it on your iPhone. Secondly, it might be possible that you are not typing the correct password on your device. And thirdly, you need to need to check that you have properly set up your Yahoo account on the iPhone. In case the problem continues, you can consult an expert of Yahoo as soon as possible.
To help such community, there are a number of third party Yahoo customer care service providers
who provide phone support as well as online helpline Chat support.