Consistency.
WHAT TO ENSURE
IMAP on every device The same folder mapping The same account settings
WHY
So the mailbox looks the same everywhere.
WHAT GOES WRONG WITHOUT IT
Sent mail missing on some devices Mail read on one and unread on another Mail deleted on one and present on another
WHAT TO CHECK ON EACH DEVICE
Account type Folder mapping for Sent, Drafts and Trash Which folders are subscribed
WHEN ADDING A NEW DEVICE
Configure it the same way as the others.
WHEN CHANGING THE PASSWORD
Update every device.
Including any you use rarely.
A device with the old password prompts repeatedly and may cause a block.
FOR SHARED MAILBOXES
Several people accessing one mailbox by IMAP works.
Actions by one are visible to all.
Agree how it is managed.
WHAT TO AVOID
Mixing POP and IMAP across devices.
