Hi there Gijo530.
Welcome to the Apple Support Communities. It sounds like you're unable to add Yahoo back to your iPhone. I rely on email too, and it's my pleasure to help you out tonight.
Can you log into your Yahoo mail on the site? Verify there first.
Then restart your iPhone.
Then try adding your Yahoo mail account back to your iPhone.
Please let me know if you're able to set up Yahoo mail on your iPhone.
Take care.
Welcome to the Apple Support Communities. It sounds like you're unable to add Yahoo back to your iPhone. I rely on email too, and it's my pleasure to help you out tonight.
Can you log into your Yahoo mail on the site? Verify there first.
Then restart your iPhone.
Restart your iPhone, iPad, or iPod touch
Then try adding your Yahoo mail account back to your iPhone.
Set up an email account on your iPhone, iPad, or iPod touch
Please let me know if you're able to set up Yahoo mail on your iPhone.
Take care.