Hi there and welcome
What exactly happens when you try to get mail now on the iPhone?
And what is the part of your email address after the @ ?
Please let me know
On the iPhone, go to Settings, Mail then press on the account and press Delete Account
Once done, go back to Settings, Mail, then add the email account again as you will be adding the account with the correct password.
Once done it will then work again
Let me know the results please.