How do I resolve email issues with multiple accounts on iPhone?

Hi there

Please try this

1. Check and Update Passwords

If you recently changed your password on Gmail, Outlook, Yahoo, or another provider, your iPhone needs the updated credentials:

• Go to Settings > Apps > Mail > Mail Accounts (or Settings > Mail > Accounts on older iOS versions).
• Tap the specific email account showing the error.
• Re-enter your password or tap Re-authenticate if prompted.
• Make sure Mail (and Contacts/Calendar if needed) is toggled On. 

2. Verify Account Settings & Delete/Re-add the Account

If a single account is stuck or corrupted, removing and re-adding it clears out broken cache or handshake tokens:

• Go to Settings > Apps > Mail > Mail Accounts.
• Tap the problematic account and select Delete Account (choose Delete from My iPhone).
• Restart your iPhone.
• Return to Settings > Apps > Mail > Mail Accounts > Add Account, select your provider, and sign back in. 

Apart from a few very specific places it is not possible to have multiple Apple Accounts on an iPhone. What exact problems are you having?

In Mail if you want to use a different or more than one iCloud or other mail provider account, go to: Settings -> mail -> accounts -> add account -> iCloud

Read this support article for how to add an email account to your iPhone, iPad, or iPod touch - Add an email account to your iPhone or iPad - Apple Support