If you're experiencing issues with IMAP on your iPhone running iOS 18, here are a few steps you can try:
1. Update Your Email Account Settings
Go to Settings > Mail > Accounts and select the email account you want to update. Double-check the incoming and outgoing server settings to ensure they’re correct.
2. Ensure New Data is Pushed to Your Device
Navigate to Settings > Mail > Accounts > Fetch New Data, then turn on Push to make sure new emails are automatically pushed to your device.
3. Adjust the IMAP Path Prefix
Go to Settings > Mail > Accounts > [your account name], and experiment with changing the IMAP path prefix in the advanced IMAP settings.
4. Delete and Re-add the Email Account
Go to Settings > Mail > Accounts, select the email account you want to remove, and tap Sign Out or Delete Account. Then, re-add the account and see if the issue persists.
5. Install the iOS 18.1 Beta
Check if the IMAP issues are resolved in the iOS 18.1 beta. Sometimes bugs are fixed in early updates.
6. Wait for a Bug Fix Update
Apple often releases a quick bug fix (e.g., a .0.1 update) soon after major iOS releases. You might want to wait for that.
If you're having issues specifically with iCloud Mail, Apple Support provides additional steps to troubleshoot. In general, make sure that Push is enabled so new data is automatically synced with your device.